| | |
| | | <template> |
| | | <div class="chapter" num="5"> |
| | | <div class="chapter" num="6"> |
| | | <!-- 第五单元首页 --> |
| | | <div class="page-box" page="160"> |
| | | <div v-if="showPageList.indexOf(160) > -1"> |
| | | <h1 id="a009"><img class="img-0" alt="" src="../../assets/images/dy5.jpg" /></h1> |
| | | <h1 id="a009"> |
| | | <img class="img-0" alt="" src="../../assets/images/dy5.jpg" /> |
| | | </h1> |
| | | <div class="padding-116"> |
| | | <p> |
| | | 中华优秀传统文化源远流长、博大精深,是中华文明的智慧结晶.成语“周而复始”出自《汉书·礼乐志》,“精健日月,星辰度理,阴阳五行,周而复始”.在现实世界中,许多事物的运动变化会呈现循环往复、周而复始的规律,我们称这种变化规律为周期性.例如,表针旋转、车轮滚动、物体简谐振动等.这些有规律的变化现象都可用三角函数来刻画. |
| | |
| | | <div class="page-box" page="161"> |
| | | <div v-if="showPageList.indexOf(161) > -1"> |
| | | <div class="padding-116"> |
| | | <p class="left"><img class="inline2" alt="" src="../../assets/images/xxmb.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="inline2" alt="" src="../../assets/images/xxmb.jpg" /> |
| | | </p> |
| | | <div class="fieldset"> |
| | | <p>1.角的概念推广.</p> |
| | | <p>知道推广角的意义和任意角所在的象限,能识别终边相同的角.</p> |
| | |
| | | <p>5.诱导公式.</p> |
| | | <p>知道诱导公式在三角函数求值与化简中的作用.</p> |
| | | <p>6.正弦函数、余弦函数的图像和性质.</p> |
| | | <p>会借助代数运算与几何直观,认识正弦函数、余弦函数的图像和性质;</p> |
| | | <p> |
| | | 会借助代数运算与几何直观,认识正弦函数、余弦函数的图像和性质; |
| | | </p> |
| | | <p>知道运用“五点法”可以画出正弦函数、余弦函数在一个周期上的简图.</p> |
| | | <p>7.已知三角函数值求指定范围的角.</p> |
| | | <p>知道特殊的三角函数值与[0,2<i>π</i>]范围内角的对应关系;</p> |
| | |
| | | <h2 id="b030"> |
| | | 5.1 角的概念推广<span class="fontsz1">>>>>>>>></span> |
| | | </h2> |
| | | <h3 id="c048">5.1.1 角的概念的推广<span class="fontsz2">>>></span></h3> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/wttc.jpg" /></p> |
| | | <h3 id="c048"> |
| | | 5.1.1 角的概念的推广<span class="fontsz2">>>></span> |
| | | </h3> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/wttc.jpg" /> |
| | | </p> |
| | | <p> |
| | | (1) |
| | | 中国跳水队享有奥运“梦之队”的美誉.自1984年到2016年,奥运会跳水项目一共产生了56枚奥运金牌,中国跳水队一共夺得了40枚,约占其中的71.4%.如图5-1(1) |
| | |
| | | 环青海湖国际公路自行车赛是我国规模最大、参赛队伍最多的竞赛,也是世界上海拔最高的国际性竞赛,“绿色、人文、和谐”的竞赛主题倡导体育运动应低碳环保,促进文化交流、人与自然和谐共生.如图5-1(2) |
| | | 所示,选手在骑自行车时,自行车车轮在前进和后退的过程中旋转形成的角一样吗? |
| | | </p> |
| | | <p class="center"><img class="img-b" alt="" src="../../assets/images/0166-1.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-b" alt="" src="../../assets/images/0166-1.jpg" /> |
| | | </p> |
| | | <p class="img">图5-1</p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /> |
| | | </p> |
| | | <p> |
| | | 生活中随处可见超出0°~360°范围的角.问题(1) |
| | | 中“向前翻腾一周半”和“向后翻腾两周半”的跳水动作,不仅有超出360°的“一周半”和“两周半”的角,而且旋转的方向也不同,产生的效果也不一样;问题(2) |
| | |
| | | </ul> |
| | | |
| | | <div class="padding-116"> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /> |
| | | </p> |
| | | <p> |
| | | 我们规定,一条射线绕其端点按逆时针方向旋转形成的角叫作<b>正角</b>,如图5-2(1) |
| | | 所示.按顺时针方向旋转形成的角叫作<b>负角</b>,如图5-2(2) |
| | | 所示.如果一条射线没有做任何旋转,就称它形成了一个<b>零角</b>,如图5-2(3) |
| | | 所示. |
| | | </p> |
| | | <p class="center"><img class="img-a" alt="" src="../../assets/images/0167-1.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0167-1.jpg" /> |
| | | </p> |
| | | <p class="img">图5-2</p> |
| | | <p>这样我们就把角的概念推广到了<b>任意角</b>,包括正角、负角和零角.</p> |
| | | <p> |
| | | 这样我们就把角的概念推广到了<b>任意角</b>,包括正角、负角和零角. |
| | | </p> |
| | | <div class="bk-hzjl"> |
| | | <div class="bj1-hzjl"> |
| | | <p class="left"> |
| | |
| | | 为了方便研究,通常在平面直角坐标系内讨论角.我们将角的顶点与原点重合,角的始边与<i>x</i>轴的非负半轴重合.这样,角的终边在第几象限,就说这个角是第几象限角. |
| | | </p> |
| | | <p>例如,图5-3中的690°角、-210°角分别是第四象限角和第二象限角.</p> |
| | | <p class="center"><img class="img-a" alt="" src="../../assets/images/0167-2.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0167-2.jpg" /> |
| | | </p> |
| | | <p class="img">图5-3</p> |
| | | <p> |
| | | 如果角的终边在坐标轴上,那么就认为这个角不属于任何一个象限(也称界限角).例如,0°,90°,180°,270°,360°角. |
| | | |
| | | </p> |
| | | </div> |
| | | </div> |
| | |
| | | <p>第五单元 三角函数</p> |
| | | </li> |
| | | <li> |
| | | <p><span>157</span></p> |
| | | <p><span>157-158</span></p> |
| | | </li> |
| | | </ul> |
| | | |
| | | <div class="padding-116"> |
| | | <p> |
| | | <span class="zt-ls"><b>例1</b></span> 在平面直角坐标系中,分别画出下列各角,并指出它们是第几象限角. |
| | | </p> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0168-1.jpg" /></p> |
| | | <p class="img">图5-4</p> |
| | | <p>(1) 225°;(2) -300°.</p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) |
| | | 以<i>x</i>轴的非负半轴为始边,逆时针方向旋转225°,即形成225°角,如图5-4(1) |
| | | 所示.因为225°角的终边在第三象限内,所以225°角是第三象限角. |
| | | <p class="p-btn" > |
| | | <span>(1) 225°;</span> |
| | | <span class="btn-box" @click="hadleAnswer(0)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p> |
| | | (2) |
| | | <div v-if="isShowAnswer0" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) |
| | | 以<i>x</i>轴的非负半轴为始边,逆时针方向旋转225°,即形成225°角,如图5-4(1) |
| | | 所示.因为225°角的终边在第三象限内,所以225°角是第三象限角. |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0168-1.jpg" /> |
| | | </p> |
| | | <p class="img">图5-4</p> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span>(2) -300°.</span> |
| | | <span class="btn-box" @click="hadleAnswer(1)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p v-if="isShowAnswer1" > |
| | | <span class="zt-ls"><b>解</b></span>(2) |
| | | 以<i>x</i>轴的非负半轴为始边,顺时针方向旋转300°,即形成-300°角,如图5-4(2) |
| | | 所示.因为-300°角的终边在第一象限内,所以-300°角是第一象限角. |
| | | </p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | | <div class="bj"> |
| | | <p>1.如图所示,已知锐角∠<i>AOB</i>=45°,写出下图中箭头所示角的度数.</p> |
| | | <p class="center"> |
| | | <img class="img-b" alt="" src="../../assets/images/0168-2.jpg" /> |
| | | </p> |
| | | <p class="img">第1题图</p> |
| | | <p>2.在平面直角坐标系中,分别画出下列各角,并指出它们各是第几象限角.</p> |
| | | <p class="center"> |
| | | <img class="img-b" alt="" src="../../assets/images/0168-3.jpg" /> |
| | | </p> |
| | | <p class="img">第2题图</p> |
| | | <examinations :cardList="questionData[164]" sourceType="json" inputBc="#d3edfa" |
| | | v-if="questionData"></examinations> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | <!-- 158 --> |
| | | <div class="page-box" page="165"> |
| | | <div v-if="showPageList.indexOf(165) > -1"> |
| | | <ul class="page-header-odd fl al-end"> |
| | | <li>158</li> |
| | | <li>数学.基础模块</li> |
| | | <li>上册</li> |
| | | </ul> |
| | | |
| | | <div class="padding-116"> |
| | | <div class="bj"> |
| | | <p>3.判断下列说法是否正确,正确的画“√”,错误的画“×”.</p> |
| | | <p>(1) 锐角是第一象限角,钝角是第二象限角.( )</p> |
| | | <p>(2) 小于90°的角一定是锐角.( )</p> |
| | | <p>(3) 直角是第一象限角或第二象限角.( )</p> |
| | | <p>(4) 第二象限角一定比第一象限角大.( )</p> |
| | | <p> |
| | | 4.(1) |
| | | 若0°<<i>α</i><90°,则<i>α</i>是第___象限角;若90°<<i>α</i><180°,则<i>α</i>是第___象限角;若180°<<i>α</i><270°,则<i>α</i>是第___象限角;若270°<<i>α</i><360°,则<i>α</i>是第___象限角. |
| | | </p> |
| | | <p> |
| | | (2) |
| | | 若-90°<<i>α</i><0°,则<i>α</i>是第___象限角;若-180°<<i>α</i><-90°,则<i>α</i>是第___象限角;若-270°<<i>α</i><-180°,则<i>α</i>是第___象限角;若-360°<<i>α</i><-270°,则<i>α</i>是第___象限角. |
| | | </p> |
| | | </div> |
| | | <h3 id="c049">5.1.2 终边相同的角<span class="fontsz2">>>></span></h3> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/wttc.jpg" /></p> |
| | | <h3 id="c049"> |
| | | 5.1.2 终边相同的角<span class="fontsz2">>>></span> |
| | | </h3> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/wttc.jpg" /> |
| | | </p> |
| | | <p> |
| | | 如图5-5所示,在平面直角坐标系中,分别画出了-330°,30°,390°角,观察其终边有何联系?-330°,390°与30°在数值上有什么关系? |
| | | </p> |
| | | <p class="center"><img class="img-f" alt="" src="../../assets/images/0169-1.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-f" alt="" src="../../assets/images/0169-1.jpg" /> |
| | | </p> |
| | | <p class="img">图5-5</p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /> |
| | | </p> |
| | | <p> |
| | | 观察发现,图5-5中-330°,390°与30°角终边相同,并且与30°角终边相同的这些角都可以表示成30°角与<i>k</i>个(<i>k</i>∈<b>Z</b>)周角的和,如 |
| | | </p> |
| | |
| | | </div> |
| | | </div> |
| | | </div> |
| | | <!-- 158 --> |
| | | <div class="page-box hidePage" page="165"></div> |
| | | <!-- 159 --> |
| | | <div class="page-box" page="166"> |
| | | <div v-if="showPageList.indexOf(166) > -1"> |
| | |
| | | <p>第五单元 三角函数</p> |
| | | </li> |
| | | <li> |
| | | <p><span>159</span></p> |
| | | <p><span>159-160</span></p> |
| | | </li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <p>合<i>S</i>中的任何一个元素都与30°角终边相同.</p> |
| | | <p> |
| | | 合<i>S</i>中的任何一个元素都与30°角终边相同. |
| | | 与45°,60°,70°,100°,…角终边相同的角构成的集合又应该如何表达呢? |
| | | </p> |
| | | <p>与45°,60°,70°,100°,…角终边相同的角构成的集合又应该如何表达呢?</p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /> |
| | | </p> |
| | | <p> |
| | | 一般地,所有与<i>α</i>终边相同的角,连同<i>α</i>在内,可以组成一个集合 |
| | | </p> |
| | |
| | | <p> |
| | | <span class="zt-ls"><b>例1</b></span> 在0°~360°内,找出与下列各角终边相同的角,并分别判断它们是第几象限角. |
| | | </p> |
| | | <p>(1) 600°;(2) -230°;(3) -890°.</p> |
| | | <p> |
| | | <p class="p-btn" > |
| | | <span>(1) 600°;</span> |
| | | <span class="btn-box" @click="hadleAnswer(2)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p v-if="isShowAnswer2" > |
| | | <span class="zt-ls"><b>解</b></span>(1) 因为600°=240°+360°,所以600°角与240°角终边相同,是第三象限角. |
| | | </p> |
| | | <p> |
| | | (2) 因为-230°=130°-360°,所以-230°角与130°角终边相同,是第二象限角. |
| | | <p class="p-btn" > |
| | | <span>(2) -230°;</span> |
| | | <span class="btn-box" @click="hadleAnswer(3)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p> |
| | | (3) 因为-890°=190°-3×360°,所以-890°角与190°角终边相同,是第三象限角. |
| | | <p v-if="isShowAnswer3" > |
| | | <span class="zt-ls"><b>解</b></span>(2) |
| | | 因为-230°=130°-360°,所以-230°角与130°角终边相同,是第二象限角. |
| | | </p> |
| | | <p class="p-btn" > |
| | | <span>(3) -890°.</span> |
| | | <span class="btn-box" @click="hadleAnswer(4)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p v-if="isShowAnswer4" > |
| | | <span class="zt-ls"><b>解</b></span>(3) |
| | | 因为-890°=190°-3×360°,所以-890°角与190°角终边相同,是第三象限角. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>例2</b></span> 写出下列角的集合. |
| | | </p> |
| | | <p>(1) 终边在<i>y</i>轴正半轴上的角的集合;</p> |
| | | <p>(2) 终边在<i>y</i>轴负半轴上的角的集合;</p> |
| | | <p>(3) 终边在<i>y</i>轴上的角的集合.</p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) 在0°~360°内,终边在<i>y</i>轴正半轴上的角是90°角, |
| | | <p class="p-btn" > |
| | | <span>(1) 终边在<i>y</i>轴正半轴上的角的集合;</span> |
| | | <span class="btn-box" @click="hadleAnswer(5)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p>所以,终边在<i>y</i>轴正半轴上的角的集合是</p> |
| | | <p class="center"> |
| | | <i>S</i>1={<i>β</i>|<i>β</i>=90°+<i>k</i>·360°,<i>k</i>∈<b>Z</b>}. |
| | | <div v-if="isShowAnswer5" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) 在0°~360°内,终边在<i>y</i>轴正半轴上的角是90°角, |
| | | </p> |
| | | <p>所以,终边在<i>y</i>轴正半轴上的角的集合是</p> |
| | | <p class="center"> |
| | | <i>S</i>1={<i>β</i>|<i>β</i>=90°+<i>k</i>·360°,<i>k</i>∈<b>Z</b>}. |
| | | </p> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span>(2) 终边在<i>y</i>轴负半轴上的角的集合;</span> |
| | | <span class="btn-box" @click="hadleAnswer(6)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p>(2) 在0°~360°内,终边在<i>y</i>轴负半轴上的角是270°角,</p> |
| | | <p>所以,终边在<i>y</i>轴负半轴上的角的集合是</p> |
| | | <p class="center"> |
| | | <i>S</i>2={<i>β</i>|<i>β</i>=270°+<i>k</i>·360°,<i>k</i>∈<b>Z</b>}. |
| | | <div v-if="isShowAnswer6" > |
| | | <p><span class="zt-ls"><b>解</b></span>(2) 在0°~360°内,终边在<i>y</i>轴负半轴上的角是270°角,</p> |
| | | <p>所以,终边在<i>y</i>轴负半轴上的角的集合是</p> |
| | | <p class="center"> |
| | | <i>S</i>2={<i>β</i>|<i>β</i>=270°+<i>k</i>·360°,<i>k</i>∈<b>Z</b>}. |
| | | </p> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span>(3) 终边在<i>y</i>轴上的角的集合.</span> |
| | | <span class="btn-box" @click="hadleAnswer(7)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 160 --> |
| | | <div class="page-box" page="167"> |
| | | <div v-if="showPageList.indexOf(167) > -1"> |
| | | <ul class="page-header-odd fl al-end"> |
| | | <li>160</li> |
| | | <li>数学.基础模块</li> |
| | | <li>上册</li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <p>(3) 终边在<i>y</i>轴上的角的集合是</p> |
| | | <p><i>S</i>=<i>S</i><sub>1</sub>∪<i>S</i><sub>2</sub></p> |
| | | <p> |
| | | ={<i>β</i>|<i>β</i>=90°+<i>k</i>·360°,<i>k</i>∈<b>Z</b>}∪{<i>β</i>|<i>β</i>=270°+<i>k</i>·360°,<i>k</i>∈<b>Z</b>} |
| | | <div v-if="isShowAnswer7" > |
| | | <p> <span class="zt-ls"><b>解</b></span>(3) 终边在<i>y</i>轴上的角的集合是</p> |
| | | <p><i>S</i>=<i>S</i><sub>1</sub>∪<i>S</i><sub>2</sub></p> |
| | | <p> |
| | | ={<i>β</i>|<i>β</i>=90°+<i>k</i>·360°,<i>k</i>∈<b>Z</b>}∪{<i>β</i>|<i>β</i>=270°+<i>k</i>·360°,<i>k</i>∈<b>Z</b>} |
| | | </p> |
| | | <p> |
| | | ={<i>β</i>|<i>β</i>=90°+2<i>k</i>·180°,<i>k</i>∈<b>Z</b>}∪{<i>β</i>|<i>β</i>=90°+(2<i>k</i>+1)·180°,<i>k</i>∈<b>Z</b>} |
| | | </p> |
| | | <p>={<i>β</i>|<i>β</i>=90°+<i>m</i>·180°,<i>m</i>∈<b>Z</b>}.</p> |
| | | </div> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | | <p> |
| | | ={<i>β</i>|<i>β</i>=90°+2<i>k</i>·180°,<i>k</i>∈<b>Z</b>}∪{<i>β</i>|<i>β</i>=90°+(2<i>k</i>+1)·180°,<i>k</i>∈<b>Z</b>} |
| | | </p> |
| | | <p>={<i>β</i>|<i>β</i>=90°+<i>m</i>·180°,<i>m</i>∈<b>Z</b>}.</p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /></p> |
| | | <div class="bj"> |
| | | <p>1.选择题.</p> |
| | | <p>(1) 与60°角终边相同的角的集合表示正确的是( ).</p> |
| | | <p> |
| | | <i>A</i>.{<i>β</i>|<i>β</i>=60°+<i>k</i>·360°} |
| | | <i>B</i>.{<i>β</i>|<i>β</i>=60°+<i>k</i>·180°,<i>k</i>∈<b>Z</b>} |
| | | </p> |
| | | <p><i>C</i>.{<i>β</i>|<i>β</i>=60°+<i>k</i>·360°,<i>k</i>∈<b>Z</b>}</p> |
| | | <p> |
| | | <i>D</i>.{<i>β</i>|<i>β</i>=-60°+<i>k</i>·360°,<i>k</i>∈<b>Z</b>} |
| | | </p> |
| | | <p>(2) 与-70°角终边相同的角的集合表示正确的是( ).</p> |
| | | <p><i>A</i>.{<i>α</i>|<i>α</i>=-70°+<i>k</i>·360°}</p> |
| | | <p><i>B</i>.{<i>α</i>|<i>α</i>=70°+<i>k</i>·360°,<i>k</i>∈<b>Z</b>}</p> |
| | | <p> |
| | | <i>C</i>.{<i>α</i>|<i>α</i>=-70°+<i>k</i>·180°,<i>k</i>∈<b>Z</b>} |
| | | </p> |
| | | <p> |
| | | <i>D</i>.{<i>α</i>|<i>α</i>=-70°+<i>k</i>·360°,<i>k</i>∈<b>Z</b>} |
| | | </p> |
| | | <p>2.填空题.</p> |
| | | <p> |
| | | (1) |
| | | 在0°~360°内,与-50°角终边相同的角是____,则-50°角是第___象限角; |
| | | </p> |
| | | <p> |
| | | (2) 在0°~360°内,与390°角终边相同的角是____,则390°是第___象限角; |
| | | </p> |
| | | <p> |
| | | (3) |
| | | 在0°~360°内,与-480°角终边相同的角是____,则-480°角是第___象限角; |
| | | </p> |
| | | <p> |
| | | (4) 在0°~360°内,与800°角终边相同的角是____,则800°角是第___象限角. |
| | | </p> |
| | | <p>3.写出与下列角终边相同的角的集合.</p> |
| | | <p>(1) 与0°角终边相同的角的集合是__________________;</p> |
| | | <p>(2) 与180°角终边相同的角的集合是__________________;</p> |
| | | <p>(3) 终边在<i>x</i>轴上的角的集合是__________________.</p> |
| | | <examinations :cardList="questionData[167]" sourceType="json" inputBc="#d3edfa" |
| | | v-if="questionData"></examinations> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
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| | | <div class="page-box hidePage" page="167"> |
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| | | <div class="page-box" page="168"> |
| | |
| | | <p><span>161</span></p> |
| | | </li> |
| | | </ul> |
| | | |
| | | <div class="padding-116"> |
| | | <h3 id="c050">习题5.1<span class="fontsz2">>>></span></h3> |
| | | <div class="bj"> |
| | | <p> |
| | | <span class="bj-sp"><b>水平一</b></span> |
| | | </p> |
| | | <p>1.230° 角是第( )象限角.</p> |
| | | <p>A.一</p> |
| | | <p>B.二</p> |
| | | <p>C.三</p> |
| | | <p>D.四</p> |
| | | <p>2.与-420°角终边相同的角是( ).</p> |
| | | <p>A.420°</p> |
| | | <p>B.-120°</p> |
| | | <p>C.280°</p> |
| | | <p>D.-60°</p> |
| | | <p>3.(1) 与70°角终边相同的角的集合表示为__________________;</p> |
| | | <p>(2) 与-120°角终边相同的角的集合表示为__________________.</p> |
| | | <p> |
| | | 4.在0°~360°内,找出与下列各角终边相同的角,并判断它们分别是第几象限角. |
| | | </p> |
| | | <p>(1)-285°;(2) 570°.</p> |
| | | <p> |
| | | 5.把下列各角化成<i>α</i>+<i>k</i>·360°(0°≤<i>α</i><360°,<i>k</i>∈<b>Z</b>)的形式,并指出它们是第几象限角. |
| | | </p> |
| | | <p>(1) 675°;(2) -520°.</p> |
| | | <p> |
| | | <span class="bj-sp"><b>水平二</b></span> |
| | | </p> |
| | | <p>1.找出与1 200°角终边相同且绝对值最小的负角.</p> |
| | | <p> |
| | | 2.设<i>α</i>为第二象限角,指出<math display="0"> |
| | | <mfrac> |
| | | <mi>α</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>是第几象限角. |
| | | </p> |
| | | <p> |
| | | 3.分别写出与下列各角终边相同的角组成的集合,并把满足不等式-360°<<i>β</i><360°的<i>β</i>写出来. |
| | | </p> |
| | | <p>(1) 125°;(2) -380°;(3) 485°.</p> |
| | | <examinations :cardList="questionData[168]" sourceType="json" inputBc="#d3edfa" |
| | | v-if="questionData"></examinations> |
| | | </div> |
| | | <h2 id="b031">5.2 弧度制<span class="fontsz1">>>>>>>>></span></h2> |
| | | <h3 id="c051">5.2.1 弧度制的定义<span class="fontsz2">>>></span></h3> |
| | | <h2 id="b031"> |
| | | 5.2 弧度制<span class="fontsz1">>>>>>>>></span> |
| | | </h2> |
| | | <h3 id="c051"> |
| | | 5.2.1 弧度制的定义<span class="fontsz2">>>></span> |
| | | </h3> |
| | | <p class="block"> |
| | | 2016年9月25日,具有我国自主知识产权的世界最大单口径、最灵敏的球面射电望远镜“中国天眼”在贵州平塘落成启用.这个500 |
| | | m口径球面射电望远镜 |
| | |
| | | <p> |
| | | 主要用于实现巡视宇宙中的中性氢、观测脉冲星等科学目标和空间飞行器测量与通信等应用目标. |
| | | </p> |
| | | <p class="center"><img class="img-f" alt="" src="../../assets/images/0172-2.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-f" alt="" src="../../assets/images/0172-2.jpg" /> |
| | | </p> |
| | | <p> |
| | | 在衡量天体之间的距离时,我们可以用光年、米的单位制来度量;对于面积,我们可以用平方米、公顷等不同的单位制来度量;质量可以用千克、吨等不同的单位制来度量.角的大小,我们是否也能用不同的单位制来度量? |
| | | </p> |
| | | <div class="bk"> |
| | | <div class="bj1"> |
| | | <p class="left"><img class="img-gn1" alt="" src="../../assets/images/gn.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn1" alt="" src="../../assets/images/gn.jpg" /> |
| | | </p> |
| | | </div> |
| | | <p class="block">角度制</p> |
| | | <p class="block">弧度制</p> |
| | |
| | | <p> |
| | | 在数学和其他科学研究中,经常使用另一种度量角的单位制——<b>弧度制</b>. |
| | | </p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /> |
| | | </p> |
| | | <p> |
| | | 我们规定,长度等于半径的圆弧所对的圆心角叫作1弧度的角,弧度单位用符号rad表示,读作弧度.1弧度的角就记作1 |
| | | rad,读作“1弧度”,如图5-6所示. |
| | | </p> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0173-2.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0173-2.jpg" /> |
| | | </p> |
| | | <p class="img">图5-6</p> |
| | | <p> |
| | | 根据上述规定可知,在半径为<i>r</i>的圆中,若弧长为<i>l</i>的弧所对的圆心角为<i>α</i> |
| | |
| | | </math>. |
| | | </p> |
| | | </div> |
| | | <p class="center"><img class="img-b" alt="" src="../../assets/images/0174-3.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-b" alt="" src="../../assets/images/0174-3.jpg" /> |
| | | </p> |
| | | <p class="img">图5-7</p> |
| | | <p> |
| | | 为了简便起见,以弧度为单位表示角的大小时,单位“弧度”或“rad”一般省略不写.例如,1 |
| | |
| | | </mfrac> |
| | | </math>,0. |
| | | </p> |
| | | <p>一般地,正角的弧度数为正数,负角的弧度数为负数,零角的弧度数为0.</p> |
| | | <p> |
| | | 一般地,正角的弧度数为正数,负角的弧度数为负数,零角的弧度数为0. |
| | | </p> |
| | | <p> |
| | | 当形成角的射线旋转一周后继续旋转,就可以得到弧度数大于2<i>π</i>或小于-2<i>π</i>的角.这样就可以得到任意弧度数的角. |
| | | </p> |
| | | <p> |
| | | 因此,每一个确定的角都有唯一确定的实数与它对应;反之,每一个确定的实数也都有唯一确定的角与它对应,如图5-8所示.这样,角与实数之间就建立了一一对应的关系. |
| | | </p> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0174-6.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0174-6.jpg" /> |
| | | </p> |
| | | <p class="img">图5-8</p> |
| | | <p> |
| | | <span class="zt-ls"><b>例1</b></span> 把下列各角化为弧度. |
| | | <p class="p-btn" > |
| | | <span><span class="zt-ls"><b>例1</b></span> 把下列各角化为弧度.</span> |
| | | <span class="btn-box" @click="hadleAnswer(8)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p>(1) 30°;(2) -225°;(3) 0°.</p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(1)</mo> |
| | | <msup> |
| | | <div v-if="isShowAnswer8" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(1)</mo> |
| | | <msup> |
| | | <mn>30</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mn>30</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mn>30</mn> |
| | | <mo>×</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>180</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(2)</mo> |
| | | <mo>−</mo> |
| | | <msup> |
| | | <mn>225</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mn>225</mn> |
| | | <mo>×</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>180</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mo>×</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(3)</mo> |
| | | <msup> |
| | | <mn>180</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(2)</mo> |
| | | <mo>−</mo> |
| | | <msup> |
| | | <mn>225</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mn>225</mn> |
| | | <mo>×</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>180</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(3)</mo> |
| | | <msup> |
| | | <mn>0</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mn>0</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mn>0</mn> |
| | | <mo>×</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>180</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mn>0</mn> |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>例2</b></span> 把下列各角化为角度. |
| | | <mo>×</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>180</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mn>0</mn> |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span><span class="zt-ls"><b>例2</b></span> 把下列各角化为角度.</span> |
| | | <span class="btn-box" @click="hadleAnswer(9)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p> |
| | | (1) |
| | |
| | | </mfrac> |
| | | </math>;(2) 5rad(结果精确到0.01). |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(1)</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <div v-if="isShowAnswer9" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(1)</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <msup> |
| | | <mn>180</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <msup> |
| | | <mn>180</mn> |
| | | <mn>60</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <msup> |
| | | <mn>60</mn> |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(2)</mo> |
| | | <mn>5</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | <mi mathvariant="normal">r</mi> |
| | | <mi mathvariant="normal">a</mi> |
| | | <mi mathvariant="normal">d</mi> |
| | | </mrow> |
| | | </msup> |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(2)</mo> |
| | | <mn>5</mn> |
| | | <mrow> |
| | | <mi mathvariant="normal">r</mi> |
| | | <mi mathvariant="normal">a</mi> |
| | | <mi mathvariant="normal">d</mi> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mn>5</mn> |
| | | <mo>×</mo> |
| | | <mfrac> |
| | | <mo>=</mo> |
| | | <mn>5</mn> |
| | | <mo>×</mo> |
| | | <mfrac> |
| | | <msup> |
| | | <mn>180</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mi>π</mi> |
| | | </mfrac> |
| | | <mo>≈</mo> |
| | | <msup> |
| | | <mn>180</mn> |
| | | <mn>286.44</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mi>π</mi> |
| | | </mfrac> |
| | | <mo>≈</mo> |
| | | <msup> |
| | | <mn>286.44</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | <div class="bk"> |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | </div> |
| | | <div class="bk mt-60"> |
| | | <div class="bj1"> |
| | | <p class="left"> |
| | | <img class="img-gn1" alt="" src="../../assets/images/tbts.jpg" /> |
| | |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 164 --> |
| | | <div class="page-box" page="171"> |
| | | <div v-if="showPageList.indexOf(171) > -1"> |
| | |
| | | <p> |
| | | <span class="zt-ls"><b>例3</b></span> 利用科学计算器,把下列各角进行弧度与角度的互化.(结果精确到0.01) |
| | | </p> |
| | | <p>(1) -5.6;(2) 154°13′.</p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) |
| | | 先将科学计算器的精确度设置为0.01,再将科学计算器设置为角度计算模式,科学计算器Ⅰ按<img class="inline" alt="" |
| | | src="../../assets/images/0175-1.jpg" />,科学计算器Ⅱ按<img class="inline" alt="" |
| | | src="../../assets/images/0175-2.jpg" />.之后依次按下列各键. |
| | | <p class="p-btn" > |
| | | <span>(1) -5.6;</span> |
| | | <span class="btn-box" @click="hadleAnswer(10)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0175-3.jpg" /></p> |
| | | <p>结果显示:</p> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0175-4.jpg" /></p> |
| | | <p>所以 -5.6 <i>rad</i> ≈-320.86°.</p> |
| | | <p> |
| | | (2) |
| | | 先将科学计算器的精确度设置为0.01,再将科学计算器设置为弧度计算模式,科学计算器Ⅰ按<img class="inline" alt="" |
| | | src="../../assets/images/0175-5.jpg" />,科学计算器Ⅱ按<img class="inline" alt="" |
| | | src="../../assets/images/0175-6.jpg" />.之后依次按下列各键. |
| | | </p> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0175-7.jpg" /></p> |
| | | <p>结果显示:</p> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0175-8.jpg" /></p> |
| | | <p>所以 154°13′≈2.69 rad.</p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /></p> |
| | | <div class="bj"> |
| | | <p>1.补充下列表格.</p> |
| | | <p class="img">表5-1</p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0175-9.jpg" /> |
| | | </p> |
| | | <p>2.角度与弧度互化.</p> |
| | | <p>(1) 225°=____;(2) -330°=____;</p> |
| | | <div v-if="isShowAnswer10" > |
| | | <p> |
| | | (3) |
| | | <math display="0"> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>9</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | </math>____;(4) |
| | | <math display="0"> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | </math>____. |
| | | <span class="zt-ls"><b>解</b></span>(1) |
| | | 先将科学计算器的精确度设置为0.01,再将科学计算器设置为角度计算模式,科学计算器Ⅰ按<img class="inline" alt="" |
| | | src="../../assets/images/0175-1.jpg" />,科学计算器Ⅱ按<img class="inline" alt="" |
| | | src="../../assets/images/0175-2.jpg" />.之后依次按下列各键. |
| | | </p> |
| | | <p>3.利用科学计算器,进行弧度与角度的互化.(结果精确到0.01)</p> |
| | | <p>(1) -3 <i>rad</i> =____;(2) 12°=____.</p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0175-3.jpg" /> |
| | | </p> |
| | | <p>结果显示:</p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0175-4.jpg" /> |
| | | </p> |
| | | <p>所以 -5.6 <i>rad</i> ≈-320.86°.</p> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span>(2) 154°13′.</span> |
| | | <span class="btn-box" @click="hadleAnswer(11)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <div v-if="isShowAnswer11" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(2) |
| | | 先将科学计算器的精确度设置为0.01,再将科学计算器设置为弧度计算模式,科学计算器Ⅰ按<img class="inline" alt="" |
| | | src="../../assets/images/0175-5.jpg" />,科学计算器Ⅱ按<img class="inline" alt="" |
| | | src="../../assets/images/0175-6.jpg" />.之后依次按下列各键. |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0175-7.jpg" /> |
| | | </p> |
| | | <p>结果显示:</p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0175-8.jpg" /> |
| | | </p> |
| | | <p>所以 154°13′≈2.69 rad.</p> |
| | | </div> |
| | | <iframe src="https://www.geogebra.org/scientific" frameborder="0" class="iframe-box"></iframe> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | | <div class="bj"> |
| | | <examinations :cardList="questionData[171]" sourceType="json" inputBc="#d3edfa" |
| | | v-if="questionData"></examinations> |
| | | </div> |
| | | </div> |
| | | </div> |
| | |
| | | <h3 id="c052"> |
| | | 5.2.2 弧长公式、扇形的面积公式<span class="fontsz2">>>></span> |
| | | </h3> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/wttc.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/wttc.jpg" /> |
| | | </p> |
| | | <p>学习了弧度制后,你能推导出弧度制下的弧长和扇形的面积公式吗?</p> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0176-1.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0176-1.jpg" /> |
| | | </p> |
| | | <p class="img">图5-9</p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /> |
| | | </p> |
| | | <p> |
| | | 如图5-9所示,已知半径为<i>r</i>的圆,设圆心角<i>α</i>=<i>n</i>°,且0°<<i>α</i><360°,<i>α</i>所对的<math display="0"> |
| | | <mover> |
| | |
| | | <p> |
| | | 将采用角度制表示的和弧度制表示的弧长公式与扇形的面积公式进行对比可知,采用弧度制后弧长公式和扇形的面积公式就更简洁了. |
| | | </p> |
| | | <p class="center"><img class="img-d" alt="" src="../../assets/images/0176-11.jpg" /></p> |
| | | <p> |
| | | <span class="zt-ls"><b>例1</b></span> 截至2021年4月,中国高速公路总里程约为16万千米,位居全球第一.某高速公路转弯处为一弧形高架桥,测得此处公路中线的总长为1 |
| | | 200 m,该弧形高架桥所对应的圆心角为<math display="0"> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </math>,求该弧形高架桥的转弯半径(结果精确到1 m). |
| | | <p class="center"> |
| | | <img class="img-d" alt="" src="../../assets/images/0176-11.jpg" /> |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 由题意可知,<i>l</i>=1 200,<math display="0"> |
| | | <mi>α</mi> |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例1</b></span> 截至2021年4月,中国高速公路总里程约为16万千米,位居全球第一.某高速公路转弯处为一弧形高架桥,测得此处公路中线的总长为1 |
| | | 200 m,该弧形高架桥所对应的圆心角为<math display="0"> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </math>,求该弧形高架桥的转弯半径(结果精确到1 m). |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(12)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <div v-if="isShowAnswer12" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 由题意可知,<i>l</i>=1 |
| | | 200,<math display="0"> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </math>,由<i>l</i>=<i>αr</i>可得 |
| | | </p> |
| | | <math display="block"> |
| | | <mi>r</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>l</mi> |
| | | <mi>α</mi> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1200</mn> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | <mn>1200</mn> |
| | | <mo>×</mo> |
| | | <mn>5</mn> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </math>,由<i>l</i>=<i>αr</i>可得 |
| | | </p> |
| | | <math display="block"> |
| | | <mi>r</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>l</mi> |
| | | <mi>α</mi> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1200</mn> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>1200</mn> |
| | | <mo>×</mo> |
| | | <mn>5</mn> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>2000</mn> |
| | | <mi>π</mi> |
| | | </mfrac> |
| | | <mo>≈</mo> |
| | | <mn>645</mn> |
| | | <mo stretchy="false">(</mo> |
| | | <mrow> |
| | | <mtext> </mtext> |
| | | <mi mathvariant="normal">m</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>2000</mn> |
| | | <mi>π</mi> |
| | | </mfrac> |
| | | <mo>≈</mo> |
| | | <mn>645</mn> |
| | | <mo stretchy="false">(</mo> |
| | | <mrow> |
| | | <mtext> </mtext> |
| | | <mi mathvariant="normal">m</mi> |
| | | </mrow> |
| | | <mo stretchy="false">)</mo> |
| | | <mo>.</mo> |
| | | </math> |
| | | <p>所以,该弧形高架桥的转弯半径约为645 m.</p> |
| | | |
| | | <mo stretchy="false">)</mo> |
| | | <mo>.</mo> |
| | | </math> |
| | | <p>所以,该弧形高架桥的转弯半径约为645 m.</p> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 166 --> |
| | | <div class="page-box" page="173"> |
| | | <div v-if="showPageList.indexOf(173) > -1"> |
| | | <ul class="page-header-odd fl al-end"> |
| | | <li>166</li> |
| | | <li>166-167</li> |
| | | <li>数学.基础模块</li> |
| | | <li>上册</li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0177-1.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0177-1.jpg" /> |
| | | </p> |
| | | <p class="img">图5-10</p> |
| | | <p> |
| | | <span class="zt-ls"><b>例2</b></span> 如图5-10所示,要在一块废铁皮上剪出一个扇形,用于制作一个圆锥筒,要求这个扇形的圆心角为60°,半径为90 |
| | | cm .请求出这个扇形的弧长与面积.(结果分别精确到0.01 cm和0.01 |
| | | cm<sup>2</sup>) |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例2</b></span> 如图5-10所示,要在一块废铁皮上剪出一个扇形,用于制作一个圆锥筒,要求这个扇形的圆心角为60°,半径为90 |
| | | cm .请求出这个扇形的弧长与面积.(结果分别精确到0.01 cm和0.01 |
| | | cm<sup>2</sup>) |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(13)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 由于<math display="0"> |
| | | <msup> |
| | | <mn>60</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math>, 所以 |
| | | </p> |
| | | <math display="block"> |
| | | <mtable columnalign="left" columnspacing="1em" rowspacing="4pt"> |
| | | <mtr> |
| | | <mtd> |
| | | <mi>l</mi> |
| | | <mo>=</mo> |
| | | <mi>α</mi> |
| | | <mi>r</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>×</mo> |
| | | <mn>90</mn> |
| | | <mo>=</mo> |
| | | <mn>30</mn> |
| | | <mi>π</mi> |
| | | <mo>≈</mo> |
| | | <mn>94.26</mn> |
| | | <mo stretchy="false">(</mo> |
| | | <div v-if="isShowAnswer13" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 由于<math display="0"> |
| | | <msup> |
| | | <mn>60</mn> |
| | | <mrow> |
| | | <mtext> </mtext> |
| | | <mi mathvariant="normal">c</mi> |
| | | <mi mathvariant="normal">m</mi> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | <mo stretchy="false">)</mo> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd> |
| | | <mi>S</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mi>r</mi> |
| | | <mi>l</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>×</mo> |
| | | <mn>90</mn> |
| | | <mo>×</mo> |
| | | <mn>30</mn> |
| | | <mi>π</mi> |
| | | <mo>≈</mo> |
| | | <mn>4241.70</mn> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <msup> |
| | | <mrow> |
| | | <mtext> </mtext> |
| | | <mi mathvariant="normal">c</mi> |
| | | <mi mathvariant="normal">m</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>.</mo> |
| | | </mtd> |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | <p>所以,这个扇形的弧长约为94.26 cm,面积约为4 241.70 cm<sup>2</sup>.</p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /></p> |
| | | <div class="bj"> |
| | | <p> |
| | | 1.要在一个半径为120 mm的圆形塑料上切割一片弧长为144 |
| | | mm的扇形物料,切割时,该弧所对应的圆心角(正角)为____弧度.2.若弧形花台的弧长为20 |
| | | m,该弧所对应的圆心角为1.6 rad,则该弧形花台对应的转弯半径是____m. |
| | | </p> |
| | | <p> |
| | | 3.若扇形的圆心角为<math display="0"> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>6</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math>,半径为5 cm,则此扇形的弧长为____cm,面积为____cm<sup>2</sup>. |
| | | </math>, 所以 |
| | | </p> |
| | | <math display="block"> |
| | | <mtable columnalign="left" columnspacing="1em" rowspacing="4pt"> |
| | | <mtr> |
| | | <mtd> |
| | | <mi>l</mi> |
| | | <mo>=</mo> |
| | | <mi>α</mi> |
| | | <mi>r</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>×</mo> |
| | | <mn>90</mn> |
| | | <mo>=</mo> |
| | | <mn>30</mn> |
| | | <mi>π</mi> |
| | | <mo>≈</mo> |
| | | <mn>94.26</mn> |
| | | <mo stretchy="false">(</mo> |
| | | <mrow> |
| | | <mtext> </mtext> |
| | | <mi mathvariant="normal">c</mi> |
| | | <mi mathvariant="normal">m</mi> |
| | | </mrow> |
| | | <mo stretchy="false">)</mo> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd> |
| | | <mi>S</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mi>r</mi> |
| | | <mi>l</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>×</mo> |
| | | <mn>90</mn> |
| | | <mo>×</mo> |
| | | <mn>30</mn> |
| | | <mi>π</mi> |
| | | <mo>≈</mo> |
| | | <mn>4241.70</mn> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <msup> |
| | | <mrow> |
| | | <mtext> </mtext> |
| | | <mi mathvariant="normal">c</mi> |
| | | <mi mathvariant="normal">m</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>.</mo> |
| | | </mtd> |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | <p> |
| | | 所以,这个扇形的弧长约为94.26 cm,面积约为4 241.70 cm<sup>2</sup>. |
| | | </p> |
| | | </div> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | | <div class="bj"> |
| | | <examinations :cardList="questionData[173]" sourceType="json" inputBc="#d3edfa" |
| | | v-if="questionData"></examinations> |
| | | </div> |
| | | <h3 id="c053">习题5.2<span class="fontsz2">>>></span></h3> |
| | | <div class="bj"> |
| | | <p> |
| | | <span class="bj-sp"><b>水平一</b></span> |
| | | </p> |
| | | <p>1.在下图中填入适当的值.</p> |
| | | <p class="center"> |
| | | <img class="img-f" alt="" src="../../assets/images/0177-5.jpg" /> |
| | | </p> |
| | | <p class="img">第1题图</p> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 167 --> |
| | | <div class="page-box" page="174"> |
| | | <div v-if="showPageList.indexOf(174) > -1"> |
| | | <ul class="page-header-box"> |
| | | <li> |
| | | <p>第五单元 三角函数</p> |
| | | </li> |
| | | <li> |
| | | <p><span>167</span></p> |
| | | </li> |
| | | </ul> |
| | | |
| | | <div class="padding-116"> |
| | | <div class="bj"> |
| | | <p>2.角度与弧度互化.</p> |
| | | <p>(1) 135°=____;(2) -225°=____;</p> |
| | | <p> |
| | | (3) -300°=___;(4) |
| | | <math display="0"> |
| | | <mfrac> |
| | | <mn>2</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mi>π</mi> |
| | | <mo>=</mo> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | (5) |
| | | <math display="0"> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | </math>;(6)-3<i>π</i>=____. |
| | | </p> |
| | | <p> |
| | | 3.(1) 若<math display="0"> |
| | | <mi>α</mi> |
| | | <mo>∈</mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>,</mo> |
| | | <mi>π</mi> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>,则<i>α</i>是第____象限角,<math display="0"> |
| | | <mfrac> |
| | | <mi>α</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>是第____象限角; |
| | | </p> |
| | | <p> |
| | | (2) 若<math display="0"> |
| | | <mi>α</mi> |
| | | <mo>∈</mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mi>π</mi> |
| | | <mo>,</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>,则<i>α</i>是第____象限角,<math display="0"> |
| | | <mfrac> |
| | | <mi>α</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>是第____象限角. |
| | | </p> |
| | | <p>4.三角形的三个内角的度数之比为1∶2∶3,求最小内角的弧度数.</p> |
| | | <p>5.经过1 <i>h</i>,钟表的时针和分针各转了多少度?分别是多少弧度?</p> |
| | | <p> |
| | | <span class="bj-sp"><b>水平二</b></span> |
| | | </p> |
| | | <p>1.已知扇形的面积为2,扇形的圆心角的弧度数为4,求该扇形的周长.</p> |
| | | <p> |
| | | 2.要在半径为100 cm的圆金属板上截取一块扇形板,使它的弧长为112 |
| | | cm,求该弧所对的圆心角的弧度数与角度数.(结果精确到1°) |
| | | </p> |
| | | <p> |
| | | 3.已知长50 cm 的弧所对的圆心角为200°,求该弧所在圆的半径.(结果精确到1 |
| | | cm) |
| | | </p> |
| | | <examinations :cardList="questionData[174]" sourceType="json" inputBc="#d3edfa" |
| | | v-if="questionData"></examinations> |
| | | </div> |
| | | <h2 id="b032"> |
| | | 5.3 任意角的正弦函数、余弦函数和正切函数<span class="fontsz1">>>>>>>>></span> |
| | |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 167 --> |
| | | <div class="page-box hidePage" page="174"></div> |
| | | <!-- 168 --> |
| | | <div class="page-box" page="175"> |
| | | <div v-if="showPageList.indexOf(175) > -1"> |
| | |
| | | </ul> |
| | | |
| | | <div class="padding-116"> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0179-1.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0179-1.jpg" /> |
| | | </p> |
| | | <p class="img">图5-12</p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/wttc.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/wttc.jpg" /> |
| | | </p> |
| | | <p> |
| | | 现在我们将一个锐角<i>α</i>放入平面直角坐标系中,使得顶点与原点重合,始边与<i>x</i>轴的非负半轴重合,如图5-12所示.已知点<i>P</i>(<i>x</i>,<i>y</i>)是锐角<i>α</i>终边上的任意一点,点 |
| | | <i>P</i>与原点<i>O</i>的距离<i>OP</i>=<i>r</i>(<i>r</i>>0),你能利用锐角三角函数的定义计算出锐角<i>α</i>所对应的三角函数值吗? |
| | | </p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /> |
| | | </p> |
| | | <p> |
| | | 过点<i>P</i>作<i>x</i>轴的垂线,垂足为<i>M</i>,则线段<i>OM</i>的长度为<i>x</i>,线段<i>MP</i>的长度为<i>y</i>. |
| | | </p> |
| | |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </math> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /> |
| | | </p> |
| | | <p>在弧度制下,我们已将<i>α</i>的范围扩展到了全体实数.</p> |
| | | <p class="center"><img class="img-f" alt="" src="../../assets/images/0179-4.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-f" alt="" src="../../assets/images/0179-4.jpg" /> |
| | | </p> |
| | | <p class="img">图5-13</p> |
| | | <p> |
| | | 一般地,如图5-13所示,当<i>α</i>为任意角时,点<i>P</i>(<i>x</i>,<i>y</i>)是<i>α</i>的终边上异于原点的任意一点,点<i>P</i>到原点的距离为<math |
| | |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 169 --> |
| | | <div class="page-box" page="176"> |
| | | <div v-if="showPageList.indexOf(176) > -1"> |
| | |
| | | </li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <p> |
| | | <span class="zt-ls"><b>例1</b></span> 如图5-14所示,已知<i>α</i>的终边经过点 <i>P</i>(3,-4), |
| | | 求sin<i>α</i>,cos<i>α</i>,tan<i>α</i>的值. |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例1</b></span> 如图5-14所示,已知<i>α</i>的终边经过点 <i>P</i>(3,-4), |
| | | 求sin<i>α</i>,cos<i>α</i>,tan<i>α</i>的值. |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(14)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0180-3.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0180-3.jpg" /> |
| | | </p> |
| | | <p class="img">图5-14</p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 由已知有<i>x</i>=3,<i>y</i>=-4, |
| | | </p> |
| | | <p>则</p> |
| | | <math display="block"> |
| | | <mi>r</mi> |
| | | <mo>=</mo> |
| | | <msqrt> |
| | | <msup> |
| | | <mn>3</mn> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo>+</mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mn>4</mn> |
| | | <msup> |
| | | <mo stretchy="false">)</mo> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | </msqrt> |
| | | <mo>=</mo> |
| | | <mn>5</mn> |
| | | <mo>.</mo> |
| | | </math> |
| | | <p>于是</p> |
| | | <math display="block"> |
| | | <mtable columnalign="left" columnspacing="1em" rowspacing="4pt"> |
| | | <mtr> |
| | | <mtd> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>y</mi> |
| | | <mi>r</mi> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>4</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo>,</mo> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>x</mi> |
| | | <mi>r</mi> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo>,</mo> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>y</mi> |
| | | <mi>x</mi> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>4</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </mtd> |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /></p> |
| | | <div class="bj"> |
| | | <p>1.(1) 正弦函数表示为<i>y</i>=____,<i>x</i>∈____;</p> |
| | | <p>(2) 余弦函数表示为<i>y</i>=____,<i>x</i>∈____;</p> |
| | | <p>(3) 正切函数表示为<i>y</i>=____,<i>x</i>≠____.</p> |
| | | <div v-if="isShowAnswer36" > |
| | | <p> |
| | | 2.若<i>α</i>的终边过点(-8,6),则sin<i>α</i>=____,cos<i>α</i>=____,tan<i>α</i>= |
| | | ____. |
| | | <span class="zt-ls"><b>解</b></span> |
| | | 由已知有<i>x</i>=3,<i>y</i>=-4, |
| | | </p> |
| | | <p> |
| | | 3.若<i>α</i>的终边过点(5,12),则sin<i>α</i>=____,cos<i>α</i>=____,tan<i>α</i>= |
| | | ____. |
| | | </p> |
| | | <p>则</p> |
| | | <math display="block"> |
| | | <mi>r</mi> |
| | | <mo>=</mo> |
| | | <msqrt> |
| | | <msup> |
| | | <mn>3</mn> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo>+</mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mn>4</mn> |
| | | <msup> |
| | | <mo stretchy="false">)</mo> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | </msqrt> |
| | | <mo>=</mo> |
| | | <mn>5</mn> |
| | | <mo>.</mo> |
| | | </math> |
| | | <p>于是</p> |
| | | <math display="block"> |
| | | <mtable columnalign="left" columnspacing="1em" rowspacing="4pt"> |
| | | <mtr> |
| | | <mtd> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>y</mi> |
| | | <mi>r</mi> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>4</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo>,</mo> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>x</mi> |
| | | <mi>r</mi> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo>,</mo> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>y</mi> |
| | | <mi>x</mi> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>4</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </mtd> |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | </div> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/wttc.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | | <div class="bj"> |
| | | <examinations :cardList="questionData[176]" sourceType="json" inputBc="#d3edfa" |
| | | v-if="questionData"></examinations> |
| | | </div> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/wttc.jpg" /> |
| | | </p> |
| | | <p> |
| | | 从<i>α</i>的正弦、余弦和正切的定义与实例可知,任意角的正弦值、余弦值和正切值在不同的象限有不同的符号.下面我们来研究各个象限内,任意角的正弦值、余弦值和正切值的符号的规律. |
| | | </p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /> |
| | | </p> |
| | | <p> |
| | | 以第二象限角为例,根据任意角的正弦、余弦和正切的定义,试分析它们在第二象限的符号情况. |
| | | </p> |
| | | <p> |
| | | 因为<i>α</i>的终边在第二象限,任取终边上异于原点的一点<i>P</i>(<i>x</i>,<i>y</i>),有 |
| | | </p> |
| | | <p class="center"><i>x</i><0, <i>y</i>>0, <i>OP</i>= <i>r</i>>0.</p> |
| | | <p class="center"> |
| | | <i>x</i><0, <i>y</i>>0, <i>OP</i>= <i>r</i>>0. |
| | | </p> |
| | | <p>根据任意角的正弦、余弦和正切的定义可知,</p> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 170 --> |
| | | <div class="page-box" page="177"> |
| | | <div v-if="showPageList.indexOf(177) > -1"> |
| | |
| | | </p> |
| | | <p>所以,可以得出第二象限各值的符号,见表5-2.</p> |
| | | <p class="img">表5-2</p> |
| | | <p class="center"><img class="img-a" alt="" src="../../assets/images/0181-4.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0181-4.jpg" /> |
| | | </p> |
| | | <p>同理,可得出其他象限内各值的符号.</p> |
| | | <p> |
| | | 一般地,<i>α</i>为任意角,<i>P</i>(<i>x</i>,<i>y</i>)为<i>α</i>终边上异于原点的任意一点,点 |
| | |
| | | 将点<i>P</i>(<i>x</i>,<i>y</i>)的坐标与各象限角的正弦值、余弦值和正切值的符号列表,如表5-3所示. |
| | | </p> |
| | | <p class="img">表5-3</p> |
| | | <p class="center"><img class="img-a" alt="" src="../../assets/images/0181-6.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0181-6.jpg" /> |
| | | </p> |
| | | <p> |
| | | 为了便于记忆,我们将sin<i>α</i>,cos<i>α</i>,tan<i>α</i>的符号标在各象限内,如图5-15所示. |
| | | </p> |
| | |
| | | <p><span>171</span></p> |
| | | </li> |
| | | </ul> |
| | | |
| | | <div class="padding-116"> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0182-1.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-b" alt="" src="../../assets/images/0182-1.jpg" /> |
| | | </p> |
| | | <p class="img">图5-15</p> |
| | | <p> |
| | | <span class="zt-ls"><b>例2</b></span> 确定下列各三角函数值的符号. |
| | | </p> |
| | | <p> |
| | | (1) sin(-210°);(2) tan760°;(3) |
| | | <math display="0"> |
| | | <p class="p-btn" > |
| | | <span>(1) sin(-210°);</span> |
| | | <span class="btn-box" @click="hadleAnswer(15)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <div v-if="isShowAnswer15" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) 因为-210°是第二象限角,所以 |
| | | </p> |
| | | <p class="center">sin(-210°)>0.</p> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span>(2) tan760°;</span> |
| | | <span class="btn-box" @click="hadleAnswer(16)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <div v-if="isShowAnswer16" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(2) |
| | | 因为760°=40°+2×360°,可知760°角与40°角的终边相同,是第一象限角,所以 |
| | | </p> |
| | | <p class="center">tan 760°>0.</p> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span> |
| | | (3) |
| | | <math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>17</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>12</mn> |
| | | </mfrac> |
| | | </math>. |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(17)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <div v-if="isShowAnswer17" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(3) 由<math display="0"> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>17</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>12</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mfrac> |
| | | <mn>5</mn> |
| | | <mn>12</mn> |
| | | </mfrac> |
| | | <mi>π</mi> |
| | | </math>,可看出<math display="0"> |
| | | <mi>π</mi> |
| | | <mo><</mo> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>12</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>6</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>12</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>,是第三象限角, |
| | | </p> |
| | | <p>所以</p> |
| | | <math display="block"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | |
| | | </mrow> |
| | | <mn>12</mn> |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) 因为-210°是第二象限角,所以 |
| | | </p> |
| | | <p class="center">sin(-210°)>0.</p> |
| | | <p> |
| | | (2) |
| | | 因为760°=40°+2×360°,可知760°角与40°角的终边相同,是第一象限角,所以 |
| | | </p> |
| | | <p class="center">tan 760°>0.</p> |
| | | <p> |
| | | (3) 由<math display="0"> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>17</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>12</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mfrac> |
| | | <mn>5</mn> |
| | | <mn>12</mn> |
| | | </mfrac> |
| | | <mi>π</mi> |
| | | </math>,可看出<math display="0"> |
| | | <mi>π</mi> |
| | | <mo><</mo> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>12</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>6</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>12</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>,是第三象限角, |
| | | <mn>0</mn> |
| | | </math> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例3</b></span> 根据sin <i>α</i>>0,且cos <i>α</i><0,确定<i>α</i>是第几象限角. |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(18)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p>所以</p> |
| | | <math display="block"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>17</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>12</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mn>0</mn> |
| | | </math> |
| | | <p> |
| | | <span class="zt-ls"><b>例3</b></span> 根据sin <i>α</i>>0,且cos <i>α</i><0,确定<i>α</i>是第几象限角. |
| | | </p> |
| | | <p> |
| | | <p v-if="isShowAnswer18"> |
| | | <span class="zt-ls"><b>解</b></span> 因为sin |
| | | <i>α</i>>0,所以<i>α</i>的终边在第一或第二象限或<i>y</i>轴的正半轴上;又因为cos<i>α</i><0,所以<i>α</i>的终边在第二或第三象限或<i>x</i>轴的负半轴上.因此,<i>α</i>为第二象限角. |
| | | </p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | | <div class="bj"> |
| | | <p>1.用“<”“>”或“=”填空.</p> |
| | | <p> |
| | | (1) sin160°___0;(2)<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>18</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </math> |
| | | ___0; |
| | | </p> |
| | | <p>(3) tan590°___0.</p> |
| | | <p>2.(1) 若sin<i>α</i>>0,则<i>α</i>的终边在______;</p> |
| | | <p>(2) 若cos<i>α</i><0,则<i>α</i>的终边在______;</p> |
| | | <p>(3) 若tan<i>α</i>>0,则<i>α</i>的终边在第___或第___象限.</p> |
| | | <p>3.若sin<i>α</i><0,且tan<i>α</i><0,则<i>α</i>是第___象限角.</p> |
| | | <examinations :cardList="questionData[178]" sourceType="json" inputBc="#d3edfa" |
| | | v-if="questionData"></examinations> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 172 --> |
| | | <div class="page-box" page="179"> |
| | | <div v-if="showPageList.indexOf(179) > -1"> |
| | |
| | | </ul> |
| | | |
| | | <div class="padding-116"> |
| | | <p class="center"><img style="width: 24%;" alt="" src="../../assets/images/0183-1.jpg" /></p> |
| | | <p class="center"> |
| | | <img style="width: 24%" alt="" src="../../assets/images/0183-1.jpg" /> |
| | | </p> |
| | | <p class="img">图5-16</p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/wttc.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/wttc.jpg" /> |
| | | </p> |
| | | <p> |
| | | 如图5-16所示,两个三角板上有几个特殊的锐角:30°,45°,60°.初中已研究了它们对应的正弦值、余弦值和正切值.现将角的范围进行了推广,已经在平面直角坐标系中研究了各象限角的正弦值、余弦值和正切值的符号分布规律.对于在平面直角坐标系中不属于任何象限的特殊角,如0°,90°,180°,270°等,它们的正弦值、余弦值和正切值又是多少?以180°为例,试求出它的正弦值、余弦值和正切值. |
| | | </p> |
| | | <p class="center"><img class="img-f" alt="" src="../../assets/images/0183-2.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-f" alt="" src="../../assets/images/0183-2.jpg" /> |
| | | </p> |
| | | <p class="img">图5-17</p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /> |
| | | </p> |
| | | <p> |
| | | 在平面直角坐标系中,180°角的终边正好与<i>x</i>轴的负半轴重合,如图5-17所示.以坐标原点为圆心、半径为单位长度的圆(简称单位圆)与<i>x</i>轴交于点<i>P</i>(-1,0),于是有 |
| | | </p> |
| | |
| | | 一般地,取单位圆与坐标轴的交点就可以得到0°,90°,180°和270°等特殊角的正弦值、余弦值和正切值,如表5-4所示. |
| | | </p> |
| | | <p class="img">表5-4</p> |
| | | <p class="center"><img class="img-a" alt="" src="../../assets/images/0183-4.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0183-4.jpg" /> |
| | | </p> |
| | | <p>表中360°角与0°角的终边相同,对应的三角函数值也相同.</p> |
| | | </div> |
| | | </div> |
| | |
| | | <p>第五单元 三角函数</p> |
| | | </li> |
| | | <li> |
| | | <p><span>173</span></p> |
| | | <p><span>173-174</span></p> |
| | | </li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <p> |
| | | <span class="zt-ls"><b>例4</b></span> 求5sin180°-4sin90°+2tan180°-7sin270°的值. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 5sin 180°-4sin 90°+2 tan 180°-7sin |
| | | 270° |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例4</b></span> 求5sin180°-4sin90°+2tan180°-7sin270°的值. |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(19)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p>=5×0-4×1+2×0-7×(-1)</p> |
| | | <p>=3.</p> |
| | | <p> |
| | | <span class="zt-ls"><b>例5</b></span> 求<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | <mo>−</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>π</mi> |
| | | <mo>−</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>的值. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mtable displaystyle="true" |
| | | columnalign="right left right left right left right left right left right left" |
| | | columnspacing="0em 2em 0em 2em 0em 2em 0em 2em 0em 2em 0em" rowspacing="3pt"> |
| | | <mtr> |
| | | <mtd></mtd> |
| | | <mtd> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | <mo>−</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>π</mi> |
| | | <mo>−</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd> |
| | | <mo>=</mo> |
| | | </mtd> |
| | | <mtd> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mn>1</mn> |
| | | <mo stretchy="false">)</mo> |
| | | <mo>−</mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mn>1</mn> |
| | | <mo stretchy="false">)</mo> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd> |
| | | <mo>=</mo> |
| | | </mtd> |
| | | <mtd> |
| | | <mn>0</mn> |
| | | <mo>.</mo> |
| | | </mtd> |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | </p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /></p> |
| | | <div class="bj"> |
| | | <div v-if="isShowAnswer19" > |
| | | <p> |
| | | 1.<math display="0"> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>60</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>45</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mstyle scriptlevel="0"> |
| | | <mspace width="1em"></mspace> |
| | | </mstyle> |
| | | <mo stretchy="false">)</mo> |
| | | </math>( ). |
| | | <span class="zt-ls"><b>解</b></span> 5sin 180°-4sin 90°+2 tan |
| | | 180°-7sin 270° |
| | | </p> |
| | | <p> |
| | | A.<math display="0"> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | B.<math display="0"> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | C.<math display="0"> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | D.<math display="0"> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>2</mn> |
| | | </msqrt> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p>2.2cos 270°+5sin 0°+2cos 180°=____.</p> |
| | | <p> |
| | | 3.<math display="0"> |
| | | <mn>5</mn> |
| | | <p>=5×0-4×1+2×0-7×(-1)</p> |
| | | <p>=3.</p> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例5</b></span> 求<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | <mo>−</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mn>2</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>π</mi> |
| | | <mo>−</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>−</mo> |
| | | <mn>3</mn> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mn>6</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mn>0</mn> |
| | | <mo>=</mo> |
| | | </math>____. |
| | | </math>的值. |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(20)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <div v-if="isShowAnswer20" > |
| | | |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mtable displaystyle="true" |
| | | columnalign="right left right left right left right left right left right left" |
| | | columnspacing="0em 2em 0em 2em 0em 2em 0em 2em 0em 2em 0em" rowspacing="3pt"> |
| | | <mtr> |
| | | <mtd></mtd> |
| | | <mtd> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | <mo>−</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>π</mi> |
| | | <mo>−</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd> |
| | | <mo>=</mo> |
| | | </mtd> |
| | | <mtd> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mn>1</mn> |
| | | <mo stretchy="false">)</mo> |
| | | <mo>−</mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mn>1</mn> |
| | | <mo stretchy="false">)</mo> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd> |
| | | <mo>=</mo> |
| | | </mtd> |
| | | <mtd> |
| | | <mn>0</mn> |
| | | <mo>.</mo> |
| | | </mtd> |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | </p> |
| | | </div> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | | <div class="bj"> |
| | | <examinations :cardList="questionData[180] ? questionData[180][1] : []" |
| | | sourceType="json" inputBc="#d3edfa" v-if="questionData"></examinations> |
| | | </div> |
| | | <h3 id="c054">习题5.3<span class="fontsz2">>>></span></h3> |
| | | <div class="bj"> |
| | | <p> |
| | | <span class="bj-sp"><b>水平一</b></span> |
| | | </p> |
| | | <p>1.若<i>α</i>的终边经过点<i>P</i>(-3,-4),则tan<i>α</i>=( ).</p> |
| | | <p>A.-3</p> |
| | | <p>B.-4</p> |
| | | <p> |
| | | C.<math display="0"> |
| | | <mfrac> |
| | | <mn>4</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | D.<math display="0"> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p>2.(1) 若sin<i>α</i><0,则<i>α</i>的终边在______;</p> |
| | | <p>(2) 若cos<i>α</i>>0,则<i>α</i>的终边在______;</p> |
| | | <p>(3) 若tan<i>α</i><0,则<i>α</i>的终边在第___或第___象限.</p> |
| | | <p>3.用“<”“>”或“=”填空.</p> |
| | | <p>(1) sin 210°___0;(2) cos(-30°)___0;</p> |
| | | <p>(3) tan 240°___0;(4) sin 150°___0.</p> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 174 --> |
| | | <div class="page-box" page="181"> |
| | | <div v-if="showPageList.indexOf(181) > -1"> |
| | | <ul class="page-header-odd fl al-end"> |
| | | <li>174</li> |
| | | <li>数学.基础模块</li> |
| | | <li>上册</li> |
| | | </ul> |
| | | |
| | | <div class="padding-116"> |
| | | <div class="bj"> |
| | | <p> |
| | | 4.若<i>α</i>的终边经过点<i>P</i>,求sin<i>α</i>,cos<i>α</i>,tan<i>α</i>的值. |
| | | </p> |
| | | <p>(1) <i>P</i>(3,4);(2) <i>P</i>(12,-5).</p> |
| | | <p>5.计算.</p> |
| | | <p> |
| | | (1)<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mn>2</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>−</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | </math>; |
| | | </p> |
| | | <p>(2) 2sin 0°-3sin 90°+4sin 180°-5sin 270°-6sin 360°;</p> |
| | | <p> |
| | | (3)<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mn>0</mn> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mn>3</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>π</mi> |
| | | <mo>−</mo> |
| | | <mn>4</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mn>5</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | <span class="bj-sp"><b>水平二</b></span> |
| | | </p> |
| | | <p> |
| | | 1.若tan<i>α</i>·cos<i>α</i>>0,且cos<i>α</i>·sin<i>α</i><0,求<i>α</i>所在的象限. |
| | | </p> |
| | | <p> |
| | | 2.若<i>α</i>的终边经过点<i>Ρ</i>(3,<i>y</i>),且满足<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </math>,求sin<i>α</i>,tan<i>α</i>的值. |
| | | </p> |
| | | <p> |
| | | 3.已知<i>α</i>的终边经过点<i>P</i>(3<i>a</i>,-4<i>a</i>)(<i>a</i>≠0),求sin<i>α</i>,cos<i>α</i>,tan<i>α</i>的值. |
| | | </p> |
| | | <examinations :cardList="questionData[180] ? questionData[180][2] : []" |
| | | sourceType="json" inputBc="#d3edfa" v-if="questionData"></examinations> |
| | | </div> |
| | | <h2 id="b033"> |
| | | 5.4 同角三角函数的基本关系<span class="fontsz1">>>>>>>>></span> |
| | |
| | | <p> |
| | | 在上一节,我们学习了三角函数的定义以及在各个象限的符号,那么同一个角的三角函数值之间是否存在某种关系呢? |
| | | </p> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0185-4.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0185-4.jpg" /> |
| | | </p> |
| | | <p class="img">图5-18</p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /> |
| | | </p> |
| | | <p> |
| | | 我们知道,在平面直角坐标系中,单位圆是以原点为圆心、单位长度为半径的圆.下面我们利用单位圆来研究同角三角函数的基本关系.如图5-18所示,已知点<i>P</i>(<i>x</i>,<i>y</i>)是角<i>α</i>的终边与单位圆的交点.过点<i>P</i>作<i>x</i>轴的垂线,垂足为<i>M</i>,则△<i>OMP</i>是直角三角形,且<i>OM</i>=|<i>x</i>|,<i>PM</i>=|<i>y</i>|,<i>OP</i>=<i>r</i>=1. |
| | | </p> |
| | |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 174 --> |
| | | <div class="page-box hidePage" page="181"></div> |
| | | <!-- 175 --> |
| | | <div class="page-box" page="182"> |
| | | <div v-if="showPageList.indexOf(182) > -1"> |
| | |
| | | <p>第五单元 三角函数</p> |
| | | </li> |
| | | <li> |
| | | <p><span>175</span></p> |
| | | <p><span>175-176</span></p> |
| | | </li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </math> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /> |
| | | </p> |
| | | <p>一般地,可以得到同角三角函数的基本关系式.</p> |
| | | <p> |
| | | <b>(1) 平方关系:</b>sin<sup>2</sup><i>α</i>+cos<sup>2</sup><i>α</i>=1. |
| | |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>例1</b></span> 已知<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </math>, 且<i>α</i>是第四象限角,求sin<i>α</i>,tan<i>α</i>的值. |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例1</b></span> 已知<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </math>, 且<i>α</i>是第四象限角,求sin<i>α</i>,tan<i>α</i>的值. |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(21)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 因为 |
| | | <i>α</i>是第四象限角,所以sin<i>α</i><0 . |
| | | </p> |
| | | <math display="block"> |
| | | <mtable columnspacing="1em" rowspacing="4pt"> |
| | | <mtr> |
| | | <mtd> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <msqrt> |
| | | <mn>1</mn> |
| | | <mo>−</mo> |
| | | <msup> |
| | | <mi>cos</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <div v-if="isShowAnswer21" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 因为 |
| | | <i>α</i>是第四象限角,所以sin<i>α</i><0 . |
| | | </p> |
| | | <math display="block"> |
| | | <mtable columnspacing="1em" rowspacing="4pt"> |
| | | <mtr> |
| | | <mtd> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </msqrt> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <msqrt> |
| | | <mn>1</mn> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | </msqrt> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>4</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo>,</mo> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <msqrt> |
| | | <mn>1</mn> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>4</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | <msup> |
| | | <mi>cos</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </msqrt> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <msqrt> |
| | | <mn>1</mn> |
| | | <mo>−</mo> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | </msqrt> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mn>4</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>4</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </mtd> |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | <mo>,</mo> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>4</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>4</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </mtd> |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | </div> |
| | | <div class="bk"> |
| | | <div class="bj1"> |
| | | <p class="left"> |
| | |
| | | </math>.其开方后的符号是由正弦值的象限符号来确定的.同理,开方后余弦值的符号也一样. |
| | | </p> |
| | | </div> |
| | | <p> |
| | | <span class="zt-ls"><b>例2</b></span> 已知<math display="0"> |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例2</b></span> 已知<math display="0"> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>12</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </math>,且<i>α</i>是第三象限角,求sin <i>α</i>,cos <i>α</i>的值. |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(22)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <div v-if="isShowAnswer22" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | </p> |
| | | <math display="block"> |
| | | <mtext> 由 </mtext> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | |
| | | <mn>12</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </math>,且<i>α</i>是第三象限角,求sin <i>α</i>,cos <i>α</i>的值. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | </p> |
| | | <math display="block"> |
| | | <mtext> 由 </mtext> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>12</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mtext> 得, </mtext> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>12</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mtext>, 即 </mtext> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>12</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mtext>. </mtext> |
| | | </math> |
| | | <p>把①代入</p> |
| | | <math display="block"> |
| | | <msup> |
| | | <mtext> 得, </mtext> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>12</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mtext>, 即 </mtext> |
| | | <mi>sin</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>+</mo> |
| | | <msup> |
| | | <mi>cos</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mn>1</mn> |
| | | <mo>,</mo> |
| | | </math> |
| | | <p class="right">①</p> |
| | | <p>得</p> |
| | | <math display="block"> |
| | | <mtable columnspacing="1em" rowspacing="4pt"> |
| | | <mtr> |
| | | <mtd> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>12</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo>+</mo> |
| | | <msup> |
| | | <mi>cos</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mn>1</mn> |
| | | <mo>,</mo> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd> |
| | | <mfrac> |
| | | <mn>169</mn> |
| | | <mn>25</mn> |
| | | </mfrac> |
| | | <msup> |
| | | <mi>cos</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mn>1</mn> |
| | | <mo>,</mo> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd> |
| | | <msup> |
| | | <mi>cos</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>25</mn> |
| | | <mn>169</mn> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </mtd> |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | <p>因为<i>α</i>是第三象限角,所以cos<i>α</i><0.</p> |
| | | <p> |
| | | 所以<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>12</mn> |
| | | <mn>5</mn> |
| | | <mn>13</mn> |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 176 --> |
| | | <div class="page-box" page="183"> |
| | | <div v-if="showPageList.indexOf(183) > -1"> |
| | | <ul class="page-header-odd fl al-end"> |
| | | <li>176</li> |
| | | <li>数学.基础模块</li> |
| | | <li>上册</li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <p> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mtext>. </mtext> |
| | | </math> |
| | | <p>把①代入</p> |
| | | <math display="block"> |
| | | <msup> |
| | | <mi>sin</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>+</mo> |
| | | <msup> |
| | | <mi>cos</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mn>1</mn> |
| | | <mo>,</mo> |
| | | </math> |
| | | <p class="right">①</p> |
| | | <p>得</p> |
| | | <math display="block"> |
| | | <mtable columnspacing="1em" rowspacing="4pt"> |
| | | <mtr> |
| | | <mtd> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>12</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo>+</mo> |
| | | <msup> |
| | | <mi>cos</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mn>1</mn> |
| | | <mo>,</mo> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd> |
| | | <mfrac> |
| | | <mn>169</mn> |
| | | <mn>25</mn> |
| | | </mfrac> |
| | | <msup> |
| | | <mi>cos</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mn>1</mn> |
| | | <mo>,</mo> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd> |
| | | <msup> |
| | | <mi>cos</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>25</mn> |
| | | <mn>169</mn> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </mtd> |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | <p>因为<i>α</i>是第三象限角,所以cos<i>α</i><0.</p> |
| | | <p> |
| | | 所以<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>5</mn> |
| | | <mn>13</mn> |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | 把<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | |
| | | </mfrac> |
| | | </math>代入①式,得 |
| | | </p> |
| | | <math display="block"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>12</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>12</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo>×</mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <math display="block"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>12</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>12</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo>×</mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>5</mn> |
| | | <mn>13</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>5</mn> |
| | | <mn>12</mn> |
| | | <mn>13</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>12</mn> |
| | | <mn>13</mn> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </math> |
| | | <p> |
| | | <span class="zt-ls"><b>例3</b></span> 求证sin<sup>4</sup><i>α</i>-cos<sup>4</sup><i>α</i>=2sin |
| | | <sup>2</sup><i>α</i>-1. |
| | | </p> |
| | | <p> |
| | | <b>证明</b> sin<sup>4</sup><i>α</i>-cos<sup>4</sup><i>α</i>=(sin |
| | | <sup>2</sup><i>α</i>+cos<sup>2</sup><i>α</i>)(sin<sup>2</sup><i>α</i>-cos<sup>2</sup><i>α</i>) |
| | | </p> |
| | | <p>=sin<sup>2</sup><i>α</i>-cos<sup>2</sup><i>α</i></p> |
| | | <p>=sin<sup>2</sup><i>α</i>-(1-sin<sup>2</sup><i>α</i>)</p> |
| | | <p>=2sin<sup>2</sup><i>α</i>-1.</p> |
| | | <p> |
| | | <span class="zt-ls"><b>例4</b></span> 化简<math display="0"> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>−</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>−</mo> |
| | | <mn>1</mn> |
| | | </mrow> |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | </p> |
| | | <math display="block"> |
| | | <mo>由</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mn>3</mn> |
| | | <mo>,</mo> |
| | | <mo>得</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mn>3</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>.</mo> |
| | | <mtable displaystyle="true" columnalign="right left right left right left right left right left right left" |
| | | columnspacing="0em 2em 0em 2em 0em 2em 0em 2em 0em 2em 0em" rowspacing="3pt"> |
| | | <mtr> |
| | | <mtd> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>+</mo> |
| | | <mn>3</mn> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | </mtd> |
| | | <mtd> |
| | | <mi></mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mn>3</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo stretchy="false">)</mo> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>+</mo> |
| | | <mn>3</mn> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mn>3</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo stretchy="false">)</mo> |
| | | </mrow> |
| | | </mfrac> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd></mtd> |
| | | <mtd> |
| | | <mi></mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mn>14</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mn>4</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>7</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </mtd> |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | <div class="bk"> |
| | | <div class="bj1"> |
| | | <p class="left"> |
| | | <img class="img-gn1" alt="" src="../../assets/images/tbts.jpg" /> |
| | | </p> |
| | | </div> |
| | | <p class="block"> |
| | | 方法一的运算思路是由正弦函数、余弦函数变化为正切函数求出结果,我们简称为“弦化切”;方法二的运算思路是由正切函数变化为正弦函数和余弦函数的关系后求出结果,我们简称为“切化弦”. |
| | | </p> |
| | | </div> |
| | | <p> |
| | | <span class="zt-ls"><b>例5</b></span> 已知tan<i>θ</i>=-3,求<math display="0"> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>+</mo> |
| | | <mn>3</mn> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | </math>的值. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 方法一:显然cos <i>θ</i>≠0, |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>+</mo> |
| | | <mn>3</mn> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | </mrow> |
| | | <mrow> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mo>+</mo> |
| | | <mn>3</mn> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mo>×</mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mn>3</mn> |
| | | <mo stretchy="false">)</mo> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mo>+</mo> |
| | | <mn>3</mn> |
| | | <mo>×</mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mn>3</mn> |
| | | <mo stretchy="false">)</mo> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>7</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </math> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例3</b></span> 求证sin<sup>4</sup><i>α</i>-cos<sup>4</sup><i>α</i>=2sin |
| | | <sup>2</sup><i>α</i>-1. |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(23)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p>方法二:</p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <div v-if="isShowAnswer23" > |
| | | <p> |
| | | <b>证明</b> sin<sup>4</sup><i>α</i>-cos<sup>4</sup><i>α</i>=(sin |
| | | <sup>2</sup><i>α</i>+cos<sup>2</sup><i>α</i>)(sin<sup>2</sup><i>α</i>-cos<sup>2</sup><i>α</i>) |
| | | </p> |
| | | <p>=sin<sup>2</sup><i>α</i>-cos<sup>2</sup><i>α</i></p> |
| | | <p>=sin<sup>2</sup><i>α</i>-(1-sin<sup>2</sup><i>α</i>)</p> |
| | | <p>=2sin<sup>2</sup><i>α</i>-1.</p> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例4</b></span> 化简<math display="0"> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>−</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>−</mo> |
| | | <mn>1</mn> |
| | | </mrow> |
| | | </mfrac> |
| | | </math>. |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(24)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <div v-if="isShowAnswer24" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | </p> |
| | | <math display="block"> |
| | | <mo>由</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mtable displaystyle="true" |
| | | columnalign="right left right left right left right left right left right left" |
| | | <mtable displaystyle="true" columnalign="right left right left right left right left right left right left" |
| | | columnspacing="0em 2em 0em 2em 0em 2em 0em 2em 0em 2em 0em" rowspacing="3pt"> |
| | | <mtr> |
| | | <mtd> |
| | |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | </div> |
| | | <div class="bk mt-60"> |
| | | <div class="bj1"> |
| | | <p class="left"> |
| | | <img class="img-gn1" alt="" src="../../assets/images/tbts.jpg" /> |
| | | </p> |
| | | </div> |
| | | <p class="block"> |
| | | 方法一的运算思路是由正弦函数、余弦函数变化为正切函数求出结果,我们简称为“弦化切”;方法二的运算思路是由正切函数变化为正弦函数和余弦函数的关系后求出结果,我们简称为“切化弦”. |
| | | </p> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例5</b></span> 已知tan<i>θ</i>=-3,求<math display="0"> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>+</mo> |
| | | <mn>3</mn> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | </math>的值. |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(25)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <div v-if="isShowAnswer25" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 方法一:显然cos <i>θ</i>≠0, |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>+</mo> |
| | | <mn>3</mn> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | </mrow> |
| | | <mrow> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mo>+</mo> |
| | | <mn>3</mn> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mo>×</mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mn>3</mn> |
| | | <mo stretchy="false">)</mo> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mo>+</mo> |
| | | <mn>3</mn> |
| | | <mo>×</mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mn>3</mn> |
| | | <mo stretchy="false">)</mo> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>7</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | <p>方法二:</p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo>由</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mn>3</mn> |
| | | <mo>,</mo> |
| | | <mo>得</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mn>3</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mtable displaystyle="true" |
| | | columnalign="right left right left right left right left right left right left" |
| | | columnspacing="0em 2em 0em 2em 0em 2em 0em 2em 0em 2em 0em" rowspacing="3pt"> |
| | | <mtr> |
| | | <mtd> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>+</mo> |
| | | <mn>3</mn> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | </mtd> |
| | | <mtd> |
| | | <mi></mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mn>3</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo stretchy="false">)</mo> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>+</mo> |
| | | <mn>3</mn> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mn>3</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo stretchy="false">)</mo> |
| | | </mrow> |
| | | </mfrac> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd></mtd> |
| | | <mtd> |
| | | <mi></mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mn>14</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mn>4</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>7</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </mtd> |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | </p> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 176 --> |
| | | <div class="page-box hidePage" page="183"> |
| | | </div> |
| | | <!-- 177 --> |
| | | <div class="page-box" page="184"> |
| | | <div v-if="showPageList.indexOf(184) > -1"> |
| | |
| | | <p><span>177</span></p> |
| | | </li> |
| | | </ul> |
| | | |
| | | <div class="padding-116"> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | | <div class="bj"> |
| | | <p> |
| | | 1.已知<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>5</mn> |
| | | <mn>13</mn> |
| | | </mfrac> |
| | | </math>,且<i>α</i>是第二象限角,则cos<i>α</i>=____,tan<i>α</i>=____. |
| | | </p> |
| | | <p> |
| | | 2.已知<math display="0"> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <msqrt> |
| | | <mo>−</mo> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | </math>,且<i>α</i>是第四象限角,则sin<i>α</i>=____,cos <i>α</i>=____. |
| | | </p> |
| | | <p>3.化简.</p> |
| | | <p> |
| | | (1) |
| | | cos<i>α</i>·tan<i>α</i>=____;(2)(1-sin<i>x</i>)(1+sin<i>x</i>)=____. |
| | | </p> |
| | | <examinations :cardList="questionData[184] ? questionData[184][1] : []" |
| | | sourceType="json" inputBc="#d3edfa" v-if="questionData"></examinations> |
| | | </div> |
| | | <h3 id="c055">习题5.4<span class="fontsz2">>>></span></h3> |
| | | <div class="bj"> |
| | | <p> |
| | | <span class="bj-sp"><b>水平一</b></span> |
| | | </p> |
| | | <p> |
| | | 1.已知<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </math>,且<i>α</i>是第四象限角,则cos<i>α</i>=( ). |
| | | </p> |
| | | <p> |
| | | A.<math display="0"> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>4</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | B.<math display="0"> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | C.<math display="0"> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | D.<math display="0"> |
| | | <mfrac> |
| | | <mn>4</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p>2.sin<sup>2</sup>25°+cos<sup>2</sup>25°=____.</p> |
| | | <p> |
| | | 3.已知<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>,且<i>α</i>是第三象限角,则sin<i>α</i>=____,tan<i>α</i>=____. |
| | | </p> |
| | | <p> |
| | | 4.已知tan <i>α</i>=-1,且<i>α</i>是第四象限角,求sin <i>α</i>,cos |
| | | <i>α</i>的值. |
| | | </p> |
| | | <p> |
| | | 5.化简<math display="0"> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | <msup> |
| | | <mi>cos</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>−</mo> |
| | | <mn>1</mn> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>1</mn> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | <msup> |
| | | <mi>sin</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | <span class="bj-sp"><b>水平二</b></span> |
| | | </p> |
| | | <p> |
| | | 1.已知<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math>,且<math display="0"> |
| | | <mi>α</mi> |
| | | <mo>∈</mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>,</mo> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>,求cos<i>α</i>,tan<i>α</i>的值. |
| | | </p> |
| | | <p> |
| | | 2.设tan<i>α</i>=3,求<math display="0"> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>+</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | </math>的值. |
| | | </p> |
| | | <p>3.求证.</p> |
| | | <p> |
| | | (1) sin<sup>4</sup><i>α</i>+sin<sup>2</sup><i>α</i>·cos<sup>2</sup><i>α</i>+cos<sup>2</sup><i>α</i>=1; |
| | | </p> |
| | | <p> |
| | | (2) tan<sup>2</sup><i>α</i>-sin<sup>2</sup><i>α</i>=tan<sup>2</sup><i>α</i>·sin<sup>2</sup><i>α</i>. |
| | | </p> |
| | | <examinations :cardList="questionData[184] ? questionData[184][2] : []" |
| | | sourceType="json" inputBc="#d3edfa" v-if="questionData"></examinations> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 178 --> |
| | | <div class="page-box" page="185"> |
| | | <div v-if="showPageList.indexOf(185) > -1"> |
| | |
| | | <p> |
| | | 我们知道,图像的对称性是函数性质(如奇偶性)的重要几何特征.在上一节,我们借助单位圆推导了同角三角函数的基本关系式.下面,我们继续利用在平面直角坐标系中关于原点中心对称的单位圆,推导三角函数的诱导公式. |
| | | </p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/wttc.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/wttc.jpg" /> |
| | | </p> |
| | | <p> |
| | | 我们知道,<math display="0"> |
| | | <mfrac> |
| | |
| | | </mfrac> |
| | | </math>之间有什么关系? |
| | | </p> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0189-9.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0189-9.jpg" /> |
| | | </p> |
| | | <p class="img">图5-19</p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /> |
| | | </p> |
| | | <p> |
| | | 在平面直角坐标系中,由于<math display="0"> |
| | | <mfrac> |
| | |
| | | <p> |
| | | 如图5-19所示,角<i>α</i>的终边与单位圆的交点为<i>P</i>(cos<i>α</i>,sin<i>α</i>),终边继续旋转2<i>πk</i>(<i>k</i>∈<b>Z</b>)后,点<i>P</i>(cos<i>α</i>,sin<i>α</i>)又回到原来的位置,所以各三角函数值并不发生变化. |
| | | </p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /> |
| | | </p> |
| | | <p> |
| | | 我们知道,所有与<i>α</i>终边相同的角,连同<i>α</i>在内,可以组成一个集合 |
| | | </p> |
| | |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 179 --> |
| | | <div class="page-box" page="186"> |
| | | <div v-if="showPageList.indexOf(186) > -1"> |
| | |
| | | <p><span>179</span></p> |
| | | </li> |
| | | </ul> |
| | | |
| | | <div class="padding-116"> |
| | | <p> |
| | | <span class="zt-ls"><b>例1</b></span> 求下列三角函数的值. |
| | | <p class="p-btn" > |
| | | <span><span class="zt-ls"><b>例1</b></span> 求下列三角函数的值.</span> |
| | | <span class="btn-box" @click="hadleAnswer(26)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p> |
| | | (1) |
| | | <math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>13</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | </math>;(2) |
| | | <math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>;(3) tan 405°. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1)<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>13</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>; |
| | | </p> |
| | | <p> |
| | | (2) |
| | | <math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>; |
| | | </p> |
| | | <p>(3) tan405°=tan(45°+360°)=tan45°=1.</p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /></p> |
| | | <div class="bj"> |
| | | <p>1.sin 750°=( ).</p> |
| | | <p> |
| | | A.<math display="0"> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | B.<math display="0"> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | C.<math display="0"> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | D.<math display="0"> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | 2.<math display="0"> |
| | | <mi>cos</mi> |
| | | (1) |
| | | <math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>25</mn> |
| | | <mn>13</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | </math>( ). |
| | | </p> |
| | | <p> |
| | | A.<math display="0"> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | B.<math display="0"> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | C.<math display="0"> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | D.<math display="0"> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | 3.<math display="0"> |
| | | <mi>tan</mi> |
| | | </math>;(2) |
| | | <math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>7</mn> |
| | | <mn>5</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>;(3) tan 405°. |
| | | </p> |
| | | <div v-if="isShowAnswer26" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1)<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>13</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>; |
| | | </p> |
| | | <p> |
| | | (2) |
| | | <math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | </math>=( ). |
| | | </p> |
| | | <p>A.-1</p> |
| | | <p>B.1</p> |
| | | <p> |
| | | C.<math display="0"> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | </mfrac> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>; |
| | | </p> |
| | | <p> |
| | | D.<math display="0"> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | </math> |
| | | </p> |
| | | <p>(3) tan405°=tan(45°+360°)=tan45°=1.</p> |
| | | </div> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/gcsk.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | | <div class="bj"> |
| | | <examinations :cardList="questionData[186]" sourceType="json" v-if="questionData"> |
| | | </examinations> |
| | | </div> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/gcsk.jpg" /> |
| | | </p> |
| | | <p> |
| | | 如图5-20所示,<math display="0"> |
| | | <mfrac> |
| | |
| | | </mfrac> |
| | | </math>之间有什么关系? |
| | | </p> |
| | | <p class="center"><img class="img-f" alt="" src="../../assets/images/0190-25.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-f" alt="" src="../../assets/images/0190-25.jpg" /> |
| | | </p> |
| | | <p class="img">图5-20</p> |
| | | </div> |
| | | </div> |
| | |
| | | <li>上册</li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /> |
| | | </p> |
| | | <p> |
| | | 如图5-20所示,<math display="0"> |
| | | <mfrac> |
| | |
| | | <mi>α</mi> |
| | | <mo>.</mo> |
| | | </math> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0191-5.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0191-5.jpg" /> |
| | | </p> |
| | | <p class="img">图5-21</p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /> |
| | | </p> |
| | | <p> |
| | | 与任意角<i>α</i>的终边关于原点中心对称的角π+<i>α</i>的正弦函数、余弦函数和正切函数的计算公式如下. |
| | | </p> |
| | |
| | | </li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <p> |
| | | <span class="zt-ls"><b>例2</b></span> 求下列三角函数的值. |
| | | <p class="p-btn" > |
| | | <span><span class="zt-ls"><b>例2</b></span> 求下列三角函数的值. </span> |
| | | <span class="btn-box" @click="hadleAnswer(27)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p> |
| | | (1) sin 225°;(2) |
| | |
| | | </mfrac> |
| | | </math>;(3) tan 570°. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1)<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>225</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <div v-if="isShowAnswer27" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1)<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>180</mn> |
| | | <mn>225</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>+</mo> |
| | | <mo>=</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <msup> |
| | | <mn>180</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>+</mo> |
| | | <msup> |
| | | <mn>45</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>45</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>45</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>2</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>; |
| | | </p> |
| | | <p> |
| | | (2)<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | </math>; |
| | | </p> |
| | | <p> |
| | | (2)<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>; |
| | | </p> |
| | | <p> |
| | | (3)<math display="0"> |
| | | <mtable displaystyle="true" |
| | | columnalign="right left right left right left right left right left right left" |
| | | columnspacing="0em 2em 0em 2em 0em 2em 0em 2em 0em 2em 0em" rowspacing="3pt"> |
| | | <mtr> |
| | | <mtd> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>570</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>; |
| | | </p> |
| | | <p> |
| | | (3)<math display="0"> |
| | | <mtable displaystyle="true" |
| | | columnalign="right left right left right left right left right left right left" |
| | | columnspacing="0em 2em 0em 2em 0em 2em 0em 2em 0em 2em 0em" rowspacing="3pt"> |
| | | <mtr> |
| | | <mtd> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>570</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | </mtd> |
| | | <mtd> |
| | | <mi></mi> |
| | | <mo>=</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <msup> |
| | | <mn>210</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>+</mo> |
| | | <msup> |
| | | <mn>360</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </msup> |
| | | </mtd> |
| | | <mtd> |
| | | <mi></mi> |
| | | <mo>=</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>=</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>210</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>+</mo> |
| | | <msup> |
| | | <mn>360</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>210</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | <mo>=</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <msup> |
| | | <mn>180</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>+</mo> |
| | | <msup> |
| | | <mn>30</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <msup> |
| | | <mn>180</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>+</mo> |
| | | <mo>=</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>30</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>30</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd></mtd> |
| | | <mtd> |
| | | <mi></mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd></mtd> |
| | | <mtd> |
| | | <mi></mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </mtd> |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | </p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /></p> |
| | | <div class="bj"> |
| | | <p>1.sin 240°( ).</p> |
| | | <p> |
| | | A.<math display="0"> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | B.<math display="0"> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | C.<math display="0"> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | D.<math display="0"> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | 2.<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>10</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | </math>( ). |
| | | </p> |
| | | <p> |
| | | A.<math display="0"> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | B.<math display="0"> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | C.<math display="0"> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | D.<math display="0"> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | 3.<math display="0"> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>21</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | </math>( ). |
| | | </p> |
| | | <p>A.-1</p> |
| | | <p> |
| | | B.<math display="0"> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p>C.1</p> |
| | | <p> |
| | | D.<math display="0"> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | </mfrac> |
| | | </mtd> |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | </p> |
| | | </div> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/gcsk.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | | <div class="bj"> |
| | | <examinations :cardList="questionData[188]" sourceType="json" v-if="questionData"> |
| | | </examinations> |
| | | </div> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/gcsk.jpg" /> |
| | | </p> |
| | | <p> |
| | | 如图5-22所示,<math display="0"> |
| | | <mfrac> |
| | |
| | | </mrow> |
| | | </math>之间有什么关系? |
| | | </p> |
| | | <p class="center"><img class="img-f" alt="" src="../../assets/images/0192-23.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-f" alt="" src="../../assets/images/0192-23.jpg" /> |
| | | </p> |
| | | <p class="img">图5-22</p> |
| | | </div> |
| | | </div> |
| | |
| | | <li>上册</li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /> |
| | | </p> |
| | | <p> |
| | | 如图5-22所示,<math display="0"> |
| | | <mfrac> |
| | |
| | | </mrow> |
| | | </math>. |
| | | </p> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0193-5.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0193-5.jpg" /> |
| | | </p> |
| | | <p class="img">图5-23</p> |
| | | <p> |
| | | 如图5-23所示,设单位圆与任意角<i>α</i>,-<i>α</i>的终边分别相交于点<i>P</i>和点<i>P</i>′,则点<i>P</i>与点<i>P</i>′关于<i>x</i>轴对称.如果点<i>P</i>的坐标是(cos<i>α</i>,sin<i>α</i>),那么点<i>P</i>′的坐标是(cos<i>α</i>,-sin<i>α</i>).由于点<i>P</i>′作为角-<i>α</i>的终边与单位圆的交点,其坐标应该是(cos(-<i>α</i>),sin(-<i>α</i>)),于是得到 |
| | |
| | | <mi>α</mi> |
| | | <mo>.</mo> |
| | | </math> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /> |
| | | </p> |
| | | <p> |
| | | 与任意角<i>α</i>的终边关于<i>x</i>轴对称的角-<i>α</i>的正弦函数、余弦函数和正切函数的计算公式如下. |
| | | </p> |
| | |
| | | 利用公式三,可以把负角的三角函数转化为正角的三角函数. |
| | | </p> |
| | | </div> |
| | | <p> |
| | | <span class="zt-ls"><b>例3</b></span> 求下列三角函数的值. |
| | | <p class="p-btn" > |
| | | <span><span class="zt-ls"><b>例3</b></span> 求下列三角函数的值.</span> |
| | | <span class="btn-box" @click="hadleAnswer(28)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p> |
| | | (1) sin(-45°);(2) cos(-390°);(3) |
| | |
| | | <mo stretchy="false">)</mo> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(1)</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <div v-if="isShowAnswer28" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(1)</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <msup> |
| | | <mn>45</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>45</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>45</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>2</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>;</mo> |
| | | </math> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(2)</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>2</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>;</mo> |
| | | </math> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(2)</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <msup> |
| | | <mn>390</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>390</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>390</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <msup> |
| | | <mn>30</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>+</mo> |
| | | <msup> |
| | | <mn>360</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>30</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>+</mo> |
| | | <msup> |
| | | <mn>360</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>30</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>;</mo> |
| | | </math> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(3)</mo> |
| | | <mtable displaystyle="true" |
| | | columnalign="right left right left right left right left right left right left" |
| | | columnspacing="0em 2em 0em 2em 0em 2em 0em 2em 0em 2em 0em" rowspacing="3pt"> |
| | | <mtr> |
| | | <mtd> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>;</mo> |
| | | </math> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(3)</mo> |
| | | <mtable displaystyle="true" |
| | | columnalign="right left right left right left right left right left right left" |
| | | columnspacing="0em 2em 0em 2em 0em 2em 0em 2em 0em 2em 0em" rowspacing="3pt"> |
| | | <mtr> |
| | | <mtd> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>16</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </mtd> |
| | | <mtd> |
| | | <mi></mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>16</mn> |
| | |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </mtd> |
| | | <mtd> |
| | | <mi></mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>16</mn> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mn>4</mn> |
| | | <mi>π</mi> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mn>4</mn> |
| | | <mi>π</mi> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd></mtd> |
| | | <mtd> |
| | | <mi></mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd></mtd> |
| | | <mtd> |
| | | <mi></mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | </mtd> |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | </p> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | </mtd> |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | </p> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | |
| | | </li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | | <div class="bj"> |
| | | <p> |
| | | 1.<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>( ). |
| | | </p> |
| | | <p> |
| | | A.<math display="0"> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | B.<math display="0"> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | C.<math display="0"> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | D.<math display="0"> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | 2.<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | </math>( ). |
| | | </p> |
| | | <p> |
| | | A.<math display="0"> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | B.<math display="0"> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | C.<math display="0"> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | D.<math display="0"> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | 3.<math display="0"> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>9</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | </math>( ). |
| | | </p> |
| | | <p>A.1</p> |
| | | <p> |
| | | B.<math display="0"> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p>C.-1</p> |
| | | <p> |
| | | D.<math display="0"> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | </math> |
| | | </p> |
| | | <examinations :cardList="questionData[190]" sourceType="json" v-if="questionData"> |
| | | </examinations> |
| | | </div> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/gcsk.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/gcsk.jpg" /> |
| | | </p> |
| | | <p> |
| | | 如图5-24所示,<i>α</i>和π-<i>α</i>所对应的角的终边关于<i>y</i>轴对称.想一想,sin<i>α</i>与sin(π-<i>α</i>),cos<i>α</i>与cos(π-<i>α</i>)之间有什么关系? |
| | | </p> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0194-14.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0194-14.jpg" /> |
| | | </p> |
| | | <p class="img">图5-24</p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /> |
| | | </p> |
| | | <p> |
| | | 如图5-24所示,设单位圆与角<i>α</i>,π-<i>α</i>的终边分别相交于点<i>P</i>和点<i>P</i>′,则点<i>P</i>与点<i>P</i>′关于<i>y</i>轴对称.如果点<i>P</i>的坐标是(cos<i>α</i>,sin<i>α</i>),那么点<i>P</i>′的坐标是(-cos<i>α</i>,sin<i>α</i>).由于点<i>P</i>′作为角π-<i>α</i>的终边与单位圆的交点,其坐标应该是(cos(π-<i>α</i>),sin(π-<i>α</i>)), |
| | | </p> |
| | |
| | | <li>上册</li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /> |
| | | </p> |
| | | <p> |
| | | 与任意角<i>α</i>的终边关于<i>y</i>轴对称的角π-<i>α</i>的正弦函数、余弦函数和正切函数的计算公式如下. |
| | | </p> |
| | |
| | | <p> |
| | | 公式一至公式四统称为三角函数的诱导公式.利用这些公式可以把任意角的三角函数转化为锐角三角函数. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>例4</b></span> 求下列三角函数的值. |
| | | <p class="p-btn" > |
| | | <span><span class="zt-ls"><b>例4</b></span> 求下列三角函数的值.</span> |
| | | <span class="btn-box" @click="hadleAnswer(29)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p> |
| | | (1) cos 135°;(2) |
| | |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(1)</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>135</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <div v-if="isShowAnswer29" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(1)</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>180</mn> |
| | | <mn>135</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <msup> |
| | | <mn>180</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>−</mo> |
| | | <msup> |
| | | <mn>45</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>45</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>45</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>2</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>;</mo> |
| | | </math> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(2)</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>8</mn> |
| | | </mfrac> |
| | | <mo>;</mo> |
| | | </math> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(2)</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>8</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>=</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>2</mn> |
| | |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | <mo>=</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mi>π</mi> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mi>π</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mo>;</mo> |
| | | </math> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(3)</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>11</mn> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mo>;</mo> |
| | | </math> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(3)</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>11</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mi>π</mi> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mi>π</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>2</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>例5</b></span> 化简:<math display="0"> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | <mo>−</mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">)</mo> |
| | | <mo>⋅</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">)</mo> |
| | | <mo>⋅</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | <mo>−</mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">)</mo> |
| | | <mo>⋅</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mi>α</mi> |
| | | <mo>−</mo> |
| | | <mi>π</mi> |
| | | <mo stretchy="false">)</mo> |
| | | </mrow> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mtable displaystyle="true" |
| | | columnalign="right left right left right left right left right left right left" |
| | | columnspacing="0em 2em 0em 2em 0em 2em 0em 2em 0em 2em 0em" rowspacing="3pt"> |
| | | <mtr> |
| | | <mtd> |
| | | <mtext> 原式 </mtext> |
| | | </mtd> |
| | | <mtd> |
| | | <mi></mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>⋅</mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">)</mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">)</mo> |
| | | </mrow> |
| | | </mfrac> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd></mtd> |
| | | <mtd> |
| | | <mi></mi> |
| | | <mo>=</mo> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例5</b></span> 化简:<math display="0"> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>⋅</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>⋅</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>⋅</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | </mrow> |
| | | </mfrac> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd></mtd> |
| | | <mtd> |
| | | <mi></mi> |
| | | <mo>=</mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">)</mo> |
| | | <mo>⋅</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">)</mo> |
| | | <mo>⋅</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | <mo>−</mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">)</mo> |
| | | <mo>⋅</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mi>α</mi> |
| | | <mo>.</mo> |
| | | </mtd> |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | <mo>−</mo> |
| | | <mi>π</mi> |
| | | <mo stretchy="false">)</mo> |
| | | </mrow> |
| | | </mfrac> |
| | | </math> |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(30)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <div v-if="isShowAnswer30" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mtable displaystyle="true" |
| | | columnalign="right left right left right left right left right left right left" |
| | | columnspacing="0em 2em 0em 2em 0em 2em 0em 2em 0em 2em 0em" rowspacing="3pt"> |
| | | <mtr> |
| | | <mtd> |
| | | <mtext> 原式 </mtext> |
| | | </mtd> |
| | | <mtd> |
| | | <mi></mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>⋅</mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">)</mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">)</mo> |
| | | </mrow> |
| | | </mfrac> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd></mtd> |
| | | <mtd> |
| | | <mi></mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>⋅</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>⋅</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>⋅</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | </mrow> |
| | | </mfrac> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd></mtd> |
| | | <mtd> |
| | | <mi></mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>.</mo> |
| | | </mtd> |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | </p> |
| | | </div> |
| | | <p><b>归纳总结</b></p> |
| | | <p> |
| | | 利用诱导公式,把任意角的三角函数值转化为锐角的三角函数值的一般步骤为: |
| | | </p> |
| | | <p class="center"><img class="img-d" alt="" src="../../assets/images/0195-6.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-d" alt="" src="../../assets/images/0195-6.jpg" /> |
| | | </p> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 185 --> |
| | | <div class="page-box" page="192"> |
| | | <div v-if="showPageList.indexOf(192) > -1"> |
| | |
| | | <p>第五单元 三角函数</p> |
| | | </li> |
| | | <li> |
| | | <p><span>185</span></p> |
| | | <p><span>185-186</span></p> |
| | | </li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <p> |
| | | 事实上,以上步骤体现了将未知转化为已知的化归思想.利用公式一至公式四,按上述步骤解决了求三角函数值这个重要而困难的问题.现在,由于计算工具的便捷使用,对于三角函数的“求值”已不是问题,但其中的思想方法在解决三角函数的各种问题中却依然有重要的作用. |
| | | </p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | | <div class="bj"> |
| | | <p>1.sin 150°=( ).</p> |
| | | <p> |
| | | A.<math display="0"> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | B.<math display="0"> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | C.<math display="0"> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | D.<math display="0"> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | 2.<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>14</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | </math>( ). |
| | | </p> |
| | | <p> |
| | | A.<math display="0"> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | B.<math display="0"> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | C.<math display="0"> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | D.<math display="0"> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | 3.<math display="0"> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>29</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | </math>( ). |
| | | </p> |
| | | <p>A.-1</p> |
| | | <p> |
| | | B.<math display="0"> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p>C.1</p> |
| | | <p> |
| | | D.<math display="0"> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | </math> |
| | | </p> |
| | | <examinations :cardList="questionData[192]" sourceType="json" v-if="questionData"> |
| | | </examinations> |
| | | </div> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/wttc.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/wttc.jpg" /> |
| | | </p> |
| | | <p> |
| | | 前面我们探究了求特殊角的三角函数值的方法,而对于不是特殊角的三角函数值又该如何求值呢?使用计算工具就能很容易地解决这个问题. |
| | | </p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /> |
| | | </p> |
| | | <p> |
| | | 利用科学计算器的<img class="inline" alt="" src="../../assets/images/0196-13.jpg" />键,可以方便地计算任意角的三角函数值. |
| | | </p> |
| | |
| | | <p> |
| | | <span class="zt-ls"><b>例6</b></span> 利用科学计算器计算.(结果精确到0.01) |
| | | </p> |
| | | <p> |
| | | (1) sin 63°52′41″;(2)<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math>;(3) |
| | | <math display="0"> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>6</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>. |
| | | <p class="p-btn" > |
| | | <span>(1) sin 63°52′41″;</span> |
| | | <span class="btn-box" @click="hadleAnswer(31)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | <!-- 186 --> |
| | | <div class="page-box" page="193"> |
| | | <div v-if="showPageList.indexOf(193) > -1"> |
| | | <ul class="page-header-odd fl al-end"> |
| | | <li>186</li> |
| | | <li>数学.基础模块</li> |
| | | <li>上册</li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) |
| | | 先将精确度设置为0.01,再将科学计算器设置为角度计算模式,然后依次按下列各键: |
| | | </p> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0197-1.jpg" /></p> |
| | | <p>结果显示:</p> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0197-2.jpg" /></p> |
| | | <p>所以 sin 63°52′41″≈0.90.</p> |
| | | <p> |
| | | (2) |
| | | 先将精确度设置为0.01,再将科学计算器设置为弧度计算模式,然后依次按下列各键: |
| | | </p> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0197-3.jpg" /></p> |
| | | <p>结果显示:</p> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0197-4.jpg" /></p> |
| | | <p> |
| | | 所以 |
| | | <math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mn>0.50</mn> |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | (3) |
| | | 先将精确度设置为0.01,再将科学计算器设置为弧度计算模式,然后依次按下列各键: |
| | | </p> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0197-6.jpg" /></p> |
| | | <p>结果显示:</p> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0197-7.jpg" /></p> |
| | | <p> |
| | | 所以<math display="0"> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>6</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>≈</mo> |
| | | <mo>−</mo> |
| | | <mn>0.73</mn> |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /></p> |
| | | <div class="bj"> |
| | | <p>1.利用科学计算器求值.(结果精确到0.01)</p> |
| | | <div v-if="isShowAnswer31" > |
| | | <p> |
| | | (1) sin 1 480°10′12″____;(2) |
| | | <span class="zt-ls"><b>解</b></span>(1) |
| | | 先将精确度设置为0.01,再将科学计算器设置为角度计算模式,然后依次按下列各键: |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0197-1.jpg" /> |
| | | </p> |
| | | <p>结果显示:</p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0197-2.jpg" /> |
| | | </p> |
| | | <p>所以 sin 63°52′41″≈0.90.</p> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span> |
| | | (2)<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math>; |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(32)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <div v-if="isShowAnswer32" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(2) |
| | | 先将精确度设置为0.01,再将科学计算器设置为弧度计算模式,然后依次按下列各键: |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0197-3.jpg" /> |
| | | </p> |
| | | <p>结果显示:</p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0197-4.jpg" /> |
| | | </p> |
| | | <p> |
| | | 所以 |
| | | <math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>9</mn> |
| | | <mn>4</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>7</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>≈</mo> |
| | | </math>____; |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mn>0.50</mn> |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | <p>(3) tan(-3.6)≈____.</p> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span> |
| | | (3) |
| | | <math display="0"> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>6</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>. |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(33)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <div v-if="isShowAnswer33" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | (3) |
| | | 先将精确度设置为0.01,再将科学计算器设置为弧度计算模式,然后依次按下列各键: |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0197-6.jpg" /> |
| | | </p> |
| | | <p>结果显示:</p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0197-7.jpg" /> |
| | | </p> |
| | | <p> |
| | | 所以<math display="0"> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>6</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>≈</mo> |
| | | <mo>−</mo> |
| | | <mn>0.73</mn> |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | </div> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | | <div class="bj"> |
| | | <examinations :cardList="questionData[193]" sourceType="json" inputBc="#d3edfa" |
| | | v-if="questionData"></examinations> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 186 --> |
| | | <div class="page-box hidePage" page="193"> |
| | | </div> |
| | | <!-- 187 --> |
| | | <div class="page-box" page="194"> |
| | | <div v-if="showPageList.indexOf(194) > -1"> |
| | |
| | | </li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <div class="bj"> |
| | | <p>2.先填“<”“>”或“=”,再用科学计算器加以验证.</p> |
| | | <p> |
| | | (1) sin 516°____0;(2) |
| | | <math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>16</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </math>; |
| | | </p> |
| | | <p>(3) tan(-1 050°)____0.</p> |
| | | </div> |
| | | <h3 id="c056">习题5.5<span class="fontsz2">>>></span></h3> |
| | | <div class="bj"> |
| | | <p> |
| | | <span class="bj-sp"><b>水平一</b></span> |
| | | </p> |
| | | <p> |
| | | 1.<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>14</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | </math>( ). |
| | | </p> |
| | | <p> |
| | | A.<math display="0"> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | B.<math display="0"> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | C.<math display="0"> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | D.<math display="0"> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p>2.tan 315°=( ).</p> |
| | | <p>A.1</p> |
| | | <p>B.-1</p> |
| | | <p> |
| | | C.<math display="0"> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | D.<math display="0"> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p>3.填空题.((7)~(9)小题用科学计算器完成,结果精确到0.001)</p> |
| | | <p>(1) sin 240°=____;(2) cos330°=____;</p> |
| | | <p> |
| | | (3) tan 225°=____;(4) |
| | | <math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>13</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | </math>; |
| | | </p> |
| | | <p> |
| | | (5) |
| | | <math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>7</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | </math>;(6) |
| | | <math display="0"> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>17</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | </math>____; |
| | | </p> |
| | | <p> |
| | | (7) |
| | | <math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>12</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo>≈</mo> |
| | | </math>____;(8) |
| | | <math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>7</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>≈</mo> |
| | | </math>____; |
| | | </p> |
| | | <p>(9) tan236°7′≈____.</p> |
| | | <p> |
| | | 4.计算<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | <mo>−</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | 5.化简<math display="0"> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">)</mo> |
| | | <mo>⋅</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mi>α</mi> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | <mo stretchy="false">)</mo> |
| | | <mo>⋅</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | <mo>−</mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">)</mo> |
| | | </mrow> |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | <span class="bj-sp"><b>水平二</b></span> |
| | | </p> |
| | | <p> |
| | | 1.已知<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mi>α</mi> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math>,求sin(π-<i>α</i>)的值. |
| | | </p> |
| | | <p>2.求值sin(-1 200°)·cos 1 290°+cos(-1 020°)·sin(-1 050°).</p> |
| | | <p> |
| | | 3.化简<math display="0"> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mi>π</mi> |
| | | <mo>−</mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">)</mo> |
| | | <mo>⋅</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | <mo>−</mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">)</mo> |
| | | <mo>⋅</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mi>α</mi> |
| | | <mo>−</mo> |
| | | <mi>π</mi> |
| | | <mo stretchy="false">)</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | <mo>−</mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mn>4</mn> |
| | | <mi>π</mi> |
| | | <mo>−</mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">)</mo> |
| | | <mo>⋅</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mn>5</mn> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">)</mo> |
| | | </mrow> |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <examinations :cardList="questionData[194]" sourceType="json" inputBc="#d3edfa" |
| | | v-if="questionData"></examinations> |
| | | </div> |
| | | </div> |
| | | </div> |
| | |
| | | <h2 id="b035"> |
| | | 5.6 正弦函数的图像和性质<span class="fontsz1">>>>>>>>></span> |
| | | </h2> |
| | | <h3 id="c057">5.6.1 正弦函数的图像<span class="fontsz2">>>></span></h3> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/gcsk.jpg" /></p> |
| | | <h3 id="c057"> |
| | | 5.6.1 正弦函数的图像<span class="fontsz2">>>></span> |
| | | </h3> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/gcsk.jpg" /> |
| | | </p> |
| | | <p> |
| | | 如果今天是2021年3月17日星期三,那么往前推7天是周几?往后推7天是周几?再过7天又是周几? |
| | | </p> |
| | |
| | | <p> |
| | | 生活中,像这样每隔7天,“周三”又会重复出现,这个“7天”就是我们常说的一周(一个周期),这种每隔一段时间便会重复出现的现象称为周期现象. |
| | | </p> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0199-1.jpg" /></p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0199-1.jpg" /> |
| | | </p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /> |
| | | </p> |
| | | <p> |
| | | 我们知道,单位圆上任意一点在圆周上旋转一周就回到原来的位置,这说明, |
| | | 在函数<i>y</i>=sin<i>x</i>中,当自变量每间隔2π个单位长度时,对应的函数值都会重复出现,即sin(<i>x</i>+2π)=sin<i>x</i>. |
| | | </p> |
| | | <div class="bk"> |
| | | <div class="bj1"> |
| | | <p class="left"><img class="img-gn1" alt="" src="../../assets/images/gn.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn1" alt="" src="../../assets/images/gn.jpg" /> |
| | | </p> |
| | | </div> |
| | | <p class="block">周期函数</p> |
| | | <p class="block">周期</p> |
| | |
| | | <p> |
| | | 一般地,对于函数<i>y</i>=<i>f</i>(<i>x</i>),如果存在一个非零常数<i>T</i>,当<i>x</i>取定义域<i>D</i>内的每一个值时,都有<i>x</i>+<i>T</i>∈<i>D</i>,并且都满足 |
| | | </p> |
| | | <p class="center"><i>f</i>(<i>x</i>+<i>T</i>)=<i>f</i>(<i>x</i>),</p> |
| | | <p class="center"> |
| | | <i>f</i>(<i>x</i>+<i>T</i>)=<i>f</i>(<i>x</i>), |
| | | </p> |
| | | <p> |
| | | 则称函数<i>y</i>=<i>f</i>(<i>x</i>)为<b>周期函数</b>,非零常数<i>T</i>叫作这个函数的一个<b>周期</b>. |
| | | </p> |
| | |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 189 --> |
| | | <div class="page-box" page="196"> |
| | | <div v-if="showPageList.indexOf(196) > -1"> |
| | |
| | | <p> |
| | | 由此可见,2π就是正弦函数<i>y</i>=sin<i>x</i>的最小正周期.为了简便起见,本书所指的三角函数的周期一般指函数的最小正周期.因此,我们说正弦函数的周期是2π. |
| | | </p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /> |
| | | </p> |
| | | <p> |
| | | <i>y</i>=sin<i>x</i>是以2π为周期的函数,所以只要画出它在一个完整周期内的图像,再利用周期性就可以得到正弦函数的图像. |
| | | </p> |
| | |
| | | 首先,列表.自变量<i>x</i>的取值如表5-5所示,利用科学计算器求出<i>y</i>=sin<i>x</i>的各个值并填入表中. |
| | | </p> |
| | | <p class="img">表5-5</p> |
| | | <p class="center"><img class="img-a" alt="" src="../../assets/images/0200-1.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0200-1.jpg" /> |
| | | </p> |
| | | <p> |
| | | 其次,描点连线.根据表中数值描点,然后用光滑的曲线把各点连接起来,绘制出在[0,2π]上的图像,如图5-25所示. |
| | | </p> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0200-2.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-b" alt="" src="../../assets/images/0200-2.jpg" /> |
| | | </p> |
| | | <p class="img">图5-25</p> |
| | | <p> |
| | | 由图5-25可以看出,决定函数<i>y</i>=sin<i>x</i>(<i>x</i>∈0,2π) |
| | |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 190 --> |
| | | <div class="page-box" page="197"> |
| | | <div v-if="showPageList.indexOf(197) > -1"> |
| | |
| | | <li>上册</li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0201-1.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-b" alt="" src="../../assets/images/0201-1.jpg" /> |
| | | </p> |
| | | <p class="img">图5-26</p> |
| | | <p>正弦函数<i>y</i>=sin<i>x</i>,<i>x</i>∈<b>R</b>的图像叫作正弦曲线.</p> |
| | | <p> |
| | | 正弦函数<i>y</i>=sin<i>x</i>,<i>x</i>∈<b>R</b>的图像叫作正弦曲线. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>例1</b></span> 用“五点法”画出下列函数在区间[0,2π]内的简图. |
| | | </p> |
| | | <p>(1) <i>y</i>=-sin<i>x</i>;(2) <i>y</i>=1+sin<i>x</i>.</p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) 列表(表5-6). |
| | | <p class="p-btn" > |
| | | <span> |
| | | (1) <i>y</i>=-sin<i>x</i>; |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(34)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p class="img">表5-6</p> |
| | | <p class="center"><img class="img-a" alt="" src="../../assets/images/0201-2.jpg" /></p> |
| | | <p> |
| | | 描点连线得<i>y</i>=-sin<i>x</i>在区间[0,2π]内的简图,如图5-27所示. |
| | | <div v-if="isShowAnswer34" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) 列表(表5-6). |
| | | </p> |
| | | <p class="img">表5-6</p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0201-2.jpg" /> |
| | | </p> |
| | | <p> |
| | | 描点连线得<i>y</i>=-sin<i>x</i>在区间[0,2π]内的简图,如图5-27所示. |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-d" alt="" src="../../assets/images/0201-3.jpg" /> |
| | | </p> |
| | | <p class="img">图5-27</p> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span>(2) <i>y</i>=1+sin<i>x</i>.</span> |
| | | <span class="btn-box" @click="hadleAnswer(35)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p class="center"><img class="img-d" alt="" src="../../assets/images/0201-3.jpg" /></p> |
| | | <p class="img">图5-27</p> |
| | | <p>(2) 列表(表5-7).</p> |
| | | <p class="img">表5-7</p> |
| | | <p class="center"><img class="img-a" alt="" src="../../assets/images/0201-4.jpg" /></p> |
| | | <p> |
| | | 描点连线得<i>y</i>=1+sin<i>x</i>在区间[0,2π]内的简图,如图5-28所示. |
| | | </p> |
| | | <p class="center"><img class="img-d" alt="" src="../../assets/images/0201-5.jpg" /></p> |
| | | <p class="img">图5-28</p> |
| | | <div v-if="isShowAnswer35" > |
| | | <p><span class="zt-ls"><b>解</b></span>(2) 列表(表5-7).</p> |
| | | <p class="img">表5-7</p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0201-4.jpg" /> |
| | | </p> |
| | | <p> |
| | | 描点连线得<i>y</i>=1+sin<i>x</i>在区间[0,2π]内的简图,如图5-28所示. |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-d" alt="" src="../../assets/images/0201-5.jpg" /> |
| | | </p> |
| | | <p class="img">图5-28</p> |
| | | </div> |
| | | <iframe src="https://www.geogebra.org/calculator" frameborder="0" class="iframe-box"></iframe> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 191 --> |
| | | <div class="page-box" page="198"> |
| | | <div v-if="showPageList.indexOf(198) > -1"> |
| | |
| | | <p><span>191</span></p> |
| | | </li> |
| | | </ul> |
| | | |
| | | <div class="padding-116"> |
| | | <div class="bk-hzjl"> |
| | | <div class="bj1-hzjl"> |
| | |
| | | <img class="img-gn2" alt="" src="../../assets/images/hzjl.jpg" /> |
| | | </p> |
| | | </div> |
| | | <examinations :cardList="questionData[198]" sourceType="json" v-if="questionData"> |
| | | </examinations> |
| | | <p class="block"> |
| | | <i>y</i>=-sin<i>x</i>与<i>y</i>=sin<i>x</i>的图像有什么关系? |
| | | <i>y</i>=1+sin<i>x</i>与<i>y</i>=sin<i>x</i>的图像有什么关系? |
| | | </p> |
| | | </div> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | | <div class="bj"> |
| | | <p> |
| | | 完成下表(表5-8),并利用“五点法”画出<i>y</i>=3sin |
| | | <i>x</i>在区间[0,2π]内的简图,并说明<i>y</i>=3sin |
| | | <i>x</i>的图像与正弦函数<i>y</i>=sin <i>x</i>的图像的区别和联系. |
| | | </p> |
| | | <p class="img">表5-8</p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0202-1.jpg" /> |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-d" alt="" src="../../assets/images/0202-2.jpg" /> |
| | | </p> |
| | | <fillInTable :queryData="queryDataOne" /> |
| | | <paint |
| | | :page="198" |
| | | :imgUrl="this.config.activeBook.resourceUrl + '/images/0103-2.jpg'" |
| | | /> |
| | | </div> |
| | | <h3 id="c058"> |
| | | 5.6.2 正弦函数的性质(一)<span class="fontsz2">>>></span> |
| | | </h3> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /> |
| | | </p> |
| | | <p> |
| | | 通过观察<i>y</i>=sin<i>x</i>的图像可知正弦函数<i>y</i>=sin<i>x</i>的性质.本节主要研究正弦函数的定义域、值域、周期性和奇偶性. |
| | | </p> |
| | |
| | | <div class="page-box" page="199"> |
| | | <div v-if="showPageList.indexOf(199) > -1"> |
| | | <ul class="page-header-odd fl al-end"> |
| | | <li>192</li> |
| | | <li>192-193</li> |
| | | <li>数学.基础模块</li> |
| | | <li>上册</li> |
| | | </ul> |
| | |
| | | <p> |
| | | 因为sin(-<i>x</i>)=-sin<i>x</i>,所以<i>y</i>=sin<i>x</i>是奇函数,其图像关于原点对称. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>例1</b></span> 已知<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mo>−</mo> |
| | | <mi>a</mi> |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>,求<i>a</i>的取值范围. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 因为 -1≤sin<i>x</i>≤1, |
| | | </p> |
| | | <p> |
| | | 所以 <math display="0"> |
| | | <mo>−</mo> |
| | | <mn>1</mn> |
| | | <mo>⩽</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mo>−</mo> |
| | | <mi>a</mi> |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>⩽</mo> |
| | | <mn>1</mn> |
| | | </math>, |
| | | </p> |
| | | <p>解得 1≤<i>a</i>≤5.</p> |
| | | <p> |
| | | <span class="zt-ls"><b>例2</b></span> 求使下列函数取得最大值、最小值的<i>x</i>的集合,并求出这些函数的最大值、最小值. |
| | | </p> |
| | | <p>(1) <i>y</i>=3+sin<i>x</i>;(2) <i>y</i>=-2sin<i>x</i>.</p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) |
| | | 使函数<i>y</i>=3+sin<i>x</i>取得最大值的<i>x</i>的集合,就是使函数<i>y</i>=sin<i>x</i>取得最大值的<i>x</i>的集合<math display="0"> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">{</mo> |
| | | <mi>x</mi> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">|</mo> |
| | | <mstyle scriptlevel="0"> |
| | | <mspace width="thinmathspace"></mspace> |
| | | </mstyle> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mn>2</mn> |
| | | <mi>k</mi> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE" fence="true" stretchy="true" symmetric="true"></mo> |
| | | </mrow> |
| | | <mo>,</mo> |
| | | <mi>k</mi> |
| | | <mo>∈</mo> |
| | | <mrow> |
| | | <mi mathvariant="bold">Z</mi> |
| | | </mrow> |
| | | <mo data-mjx-texclass="CLOSE">}</mo> |
| | | </mrow> |
| | | </math>.这时函数<i>y</i>=3+sin<i>x</i>的最大值为<i>y</i>=3+1=4. |
| | | </p> |
| | | <p> |
| | | 使函数<i>y</i>=3+sin<i>x</i>取得最小值的<i>x</i>的集合,就是使函数<i>y</i>=sin<i>x</i>取得最小值的<i>x</i>的集合<math display="0"> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">{</mo> |
| | | <mi>x</mi> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">|</mo> |
| | | <mstyle scriptlevel="0"> |
| | | <mspace width="thinmathspace"></mspace> |
| | | </mstyle> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mn>2</mn> |
| | | <mi>k</mi> |
| | | <mi>π</mi> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE" fence="true" stretchy="true" symmetric="true"></mo> |
| | | </mrow> |
| | | <mo>,</mo> |
| | | <mi>k</mi> |
| | | <mo>∈</mo> |
| | | <mrow> |
| | | <mi mathvariant="bold">Z</mi> |
| | | </mrow> |
| | | <mo data-mjx-texclass="CLOSE">}</mo> |
| | | </mrow> |
| | | </math>.这时函数<i>y</i>=3+sin<i>x</i>的最小值为<i>y</i>=3+(-1)=2. |
| | | </p> |
| | | <p> |
| | | (2) |
| | | 使函数<i>y</i>=-2sin<i>x</i>取得最大值的<i>x</i>的集合,就是使函数<i>y</i>=sin<i>x</i>取得最小值的<i>x</i>的集合<math display="0"> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">{</mo> |
| | | <mi>x</mi> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">|</mo> |
| | | <mstyle scriptlevel="0"> |
| | | <mspace width="thinmathspace"></mspace> |
| | | </mstyle> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mn>2</mn> |
| | | <mi>k</mi> |
| | | <mi>π</mi> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE" fence="true" stretchy="true" symmetric="true"></mo> |
| | | </mrow> |
| | | <mo>,</mo> |
| | | <mi>k</mi> |
| | | <mo>∈</mo> |
| | | <mrow> |
| | | <mi mathvariant="bold">Z</mi> |
| | | </mrow> |
| | | <mo data-mjx-texclass="CLOSE">}</mo> |
| | | </mrow> |
| | | </math>.这时函数<i>y</i>=-2sin<i>x</i>的最大值为<i>y</i>=-2×(-1)=2. |
| | | </p> |
| | | <p> |
| | | 使函数<i>y</i>=-2sin<i>x</i>取得最小值的<i>x</i>的集合,就是使函数<i>y</i>=sin<i>x</i>取得最大值的<i>x</i>的集合<math display="0"> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">{</mo> |
| | | <mi>x</mi> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">|</mo> |
| | | <mstyle scriptlevel="0"> |
| | | <mspace width="thinmathspace"></mspace> |
| | | </mstyle> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mn>2</mn> |
| | | <mi>k</mi> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE" fence="true" stretchy="true" symmetric="true"></mo> |
| | | </mrow> |
| | | <mo>,</mo> |
| | | <mi>k</mi> |
| | | <mo>∈</mo> |
| | | <mrow> |
| | | <mi mathvariant="bold">Z</mi> |
| | | </mrow> |
| | | <mo data-mjx-texclass="CLOSE">}</mo> |
| | | </mrow> |
| | | </math>.这时函数<i>y</i>=-2sin<i>x</i>的最小值为<i>y</i>=-2×1=-2. |
| | | </p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /></p> |
| | | <div class="bj"> |
| | | <p> |
| | | 1.已知<math display="0"> |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例1</b></span> 已知<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>a</mi> |
| | | <mn>3</mn> |
| | | <mo>−</mo> |
| | | <mn>1</mn> |
| | | <mi>a</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>,则<i>a</i>的取值范围为____. |
| | | </math>,求<i>a</i>的取值范围. |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(36)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <div v-if="isShowAnswer36" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 因为 -1≤sin<i>x</i>≤1, |
| | | </p> |
| | | <p> |
| | | 2.(1)函数<i>y</i>=1+0.6sin <i>x</i>的最大值为____, 最小值为____; |
| | | 所以 <math display="0"> |
| | | <mo>−</mo> |
| | | <mn>1</mn> |
| | | <mo>⩽</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mo>−</mo> |
| | | <mi>a</mi> |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>⩽</mo> |
| | | <mn>1</mn> |
| | | </math>, |
| | | </p> |
| | | <p>解得 1≤<i>a</i>≤5.</p> |
| | | </div> |
| | | <p> |
| | | <span class="zt-ls"><b>例2</b></span> 求使下列函数取得最大值、最小值的<i>x</i>的集合,并求出这些函数的最大值、最小值. |
| | | </p> |
| | | <p class="p-btn" > |
| | | <span> |
| | | (1) <i>y</i>=3+sin<i>x</i>; |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(37)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <div v-if="isShowAnswer37" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) |
| | | 使函数<i>y</i>=3+sin<i>x</i>取得最大值的<i>x</i>的集合,就是使函数<i>y</i>=sin<i>x</i>取得最大值的<i>x</i>的集合<math display="0"> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">{</mo> |
| | | <mi>x</mi> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">|</mo> |
| | | <mstyle scriptlevel="0"> |
| | | <mspace width="thinmathspace"></mspace> |
| | | </mstyle> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mn>2</mn> |
| | | <mi>k</mi> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE" fence="true" stretchy="true" symmetric="true"></mo> |
| | | </mrow> |
| | | <mo>,</mo> |
| | | <mi>k</mi> |
| | | <mo>∈</mo> |
| | | <mrow> |
| | | <mi mathvariant="bold">Z</mi> |
| | | </mrow> |
| | | <mo data-mjx-texclass="CLOSE">}</mo> |
| | | </mrow> |
| | | </math>.这时函数<i>y</i>=3+sin<i>x</i>的最大值为<i>y</i>=3+1=4. |
| | | </p> |
| | | <p> |
| | | 使函数<i>y</i>=3+sin<i>x</i>取得最小值的<i>x</i>的集合,就是使函数<i>y</i>=sin<i>x</i>取得最小值的<i>x</i>的集合<math display="0"> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">{</mo> |
| | | <mi>x</mi> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">|</mo> |
| | | <mstyle scriptlevel="0"> |
| | | <mspace width="thinmathspace"></mspace> |
| | | </mstyle> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mn>2</mn> |
| | | <mi>k</mi> |
| | | <mi>π</mi> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE" fence="true" stretchy="true" symmetric="true"></mo> |
| | | </mrow> |
| | | <mo>,</mo> |
| | | <mi>k</mi> |
| | | <mo>∈</mo> |
| | | <mrow> |
| | | <mi mathvariant="bold">Z</mi> |
| | | </mrow> |
| | | <mo data-mjx-texclass="CLOSE">}</mo> |
| | | </mrow> |
| | | </math>.这时函数<i>y</i>=3+sin<i>x</i>的最小值为<i>y</i>=3+(-1)=2. |
| | | </p> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 193 --> |
| | | <div class="page-box" page="200"> |
| | | <div v-if="showPageList.indexOf(200) > -1"> |
| | | <ul class="page-header-box"> |
| | | <li> |
| | | <p>第五单元 三角函数</p> |
| | | </li> |
| | | <li> |
| | | <p><span>193</span></p> |
| | | </li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <div class="bj"> |
| | | |
| | | <p class="p-btn" > |
| | | <span> |
| | | (2) <i>y</i>=-2sin<i>x</i>. |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(38)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <div v-if="isShowAnswer38" > |
| | | <p> |
| | | (2)函数<math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>2</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | </math>的最大值为____,最小值为____. |
| | | <span class="zt-ls"><b>解</b></span>(2) |
| | | 使函数<i>y</i>=-2sin<i>x</i>取得最大值的<i>x</i>的集合,就是使函数<i>y</i>=sin<i>x</i>取得最小值的<i>x</i>的集合<math display="0"> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">{</mo> |
| | | <mi>x</mi> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">|</mo> |
| | | <mstyle scriptlevel="0"> |
| | | <mspace width="thinmathspace"></mspace> |
| | | </mstyle> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mn>2</mn> |
| | | <mi>k</mi> |
| | | <mi>π</mi> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE" fence="true" stretchy="true" symmetric="true"></mo> |
| | | </mrow> |
| | | <mo>,</mo> |
| | | <mi>k</mi> |
| | | <mo>∈</mo> |
| | | <mrow> |
| | | <mi mathvariant="bold">Z</mi> |
| | | </mrow> |
| | | <mo data-mjx-texclass="CLOSE">}</mo> |
| | | </mrow> |
| | | </math>.这时函数<i>y</i>=-2sin<i>x</i>的最大值为<i>y</i>=-2×(-1)=2. |
| | | </p> |
| | | <p> |
| | | 使函数<i>y</i>=-2sin<i>x</i>取得最小值的<i>x</i>的集合,就是使函数<i>y</i>=sin<i>x</i>取得最大值的<i>x</i>的集合<math display="0"> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">{</mo> |
| | | <mi>x</mi> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">|</mo> |
| | | <mstyle scriptlevel="0"> |
| | | <mspace width="thinmathspace"></mspace> |
| | | </mstyle> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mn>2</mn> |
| | | <mi>k</mi> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE" fence="true" stretchy="true" symmetric="true"></mo> |
| | | </mrow> |
| | | <mo>,</mo> |
| | | <mi>k</mi> |
| | | <mo>∈</mo> |
| | | <mrow> |
| | | <mi mathvariant="bold">Z</mi> |
| | | </mrow> |
| | | <mo data-mjx-texclass="CLOSE">}</mo> |
| | | </mrow> |
| | | </math>.这时函数<i>y</i>=-2sin<i>x</i>的最小值为<i>y</i>=-2×1=-2. |
| | | </p> |
| | | </div> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | | <div class="bj"> |
| | | <examinations :cardList="questionData[199]" sourceType="json" inputBc="#d3edfa" |
| | | v-if="questionData"></examinations> |
| | | </div> |
| | | <h3 id="c059"> |
| | | 5.6.3 正弦函数的性质(二)<span class="fontsz2">>>></span> |
| | | </h3> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /> |
| | | </p> |
| | | <p>5.单调性.</p> |
| | | <p> |
| | | 如图5-29所示,选取正弦曲线在长度为2π的区间<math display="0"> |
| | |
| | | </mrow> |
| | | </math>内的图像进行考查. |
| | | </p> |
| | | <p class="center"><img class="img-d" alt="" src="../../assets/images/0204-3.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-d" alt="" src="../../assets/images/0204-3.jpg" /> |
| | | </p> |
| | | <p class="img">图5-29</p> |
| | | <p> |
| | | <i>y</i>=sin<i>x</i> 在区间<math display="0"> |
| | |
| | | </mrow> |
| | | </math>上都是减函数,函数值由1减小到-1. |
| | | </p> |
| | | <p><b>例</b> 不求值,利用正弦函数的单调性,比较下列各对正弦值的大小.</p> |
| | | <p> |
| | | (1)<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | </math>与<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math>;(2)<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>9</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>与<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>10</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>. |
| | | <b>例</b> 不求值,利用正弦函数的单调性,比较下列各对正弦值的大小. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) 因为 <math display="0"> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <p class="p-btn" > |
| | | <span> |
| | | (1)<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | </math>与<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>, |
| | | </mfrac> |
| | | </math>; |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(39)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p> |
| | | 而<i>y</i>=sin <i>x</i> 在<math display="0"> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">[</mo> |
| | | <div v-if="isShowAnswer39" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) 因为 <math display="0"> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>,</mo> |
| | | <mo><</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">]</mo> |
| | | </mrow> |
| | | </math>上是减函数,所以 |
| | | </p> |
| | | <math display="block"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mtext>. </mtext> |
| | | </math> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 194 --> |
| | | <div class="page-box" page="201"> |
| | | <div v-if="showPageList.indexOf(201) > -1"> |
| | | <ul class="page-header-odd fl al-end"> |
| | | <li>194</li> |
| | | <li>数学.基础模块</li> |
| | | <li>上册</li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | |
| | | <p> |
| | | (2) 因为 <math display="0"> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>9</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>10</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mn>0</mn> |
| | | </math>, |
| | | </p> |
| | | <p> |
| | | 而<i>y</i>=sin <i>x</i>在<math display="0"> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">[</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>,</mo> |
| | | <mn>0</mn> |
| | | <mo data-mjx-texclass="CLOSE">]</mo> |
| | | </mrow> |
| | | </math>上是增函数,所以 |
| | | </p> |
| | | <math display="block"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>9</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo><</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>10</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /></p> |
| | | <div class="bj"> |
| | | <p>不求值,利用正弦函数的单调性,比较下列各对正弦函数值的大小.</p> |
| | | <p> |
| | | (1) |
| | | <math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>12</mn> |
| | | </mfrac> |
| | | </math>____<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>11</mn> |
| | | </mfrac> |
| | | </math>;(2) sin 250°____sin 260°. |
| | | </math>, |
| | | </p> |
| | | <p> |
| | | 而<i>y</i>=sin <i>x</i> 在<math display="0"> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">[</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>,</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">]</mo> |
| | | </mrow> |
| | | </math>上是减函数,所以 |
| | | </p> |
| | | <math display="block"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mtext>. </mtext> |
| | | </math> |
| | | </div> |
| | | <h3 id="c060">习题5.6<span class="fontsz2">>>></span></h3> |
| | | <div class="bj"> |
| | | <p> |
| | | <span class="bj-sp"><b>水平一</b></span> |
| | | </p> |
| | | <p>1.比较大小.</p> |
| | | <p> |
| | | (1) sin 53°____sin 78°;(2) |
| | | <math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </math>____<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p>2.函数<i>y</i>=2sin <i>x</i>的最大值为____,最小值为____.</p> |
| | | <p> |
| | | 3.已知<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>a</mi> |
| | | <mo>−</mo> |
| | | <mn>1</mn> |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>,则<i>a</i>的取值范围为____. |
| | | </p> |
| | | <p> |
| | | 4.求函数<math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | </math>,<i>x</i>∈0,2π的单调区间. |
| | | </p> |
| | | <p> |
| | | 5.利用“五点法”画出函数<math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | </math>在一个周期内的图像. |
| | | </p> |
| | | <p> |
| | | <span class="bj-sp"><b>水平二</b></span> |
| | | </p> |
| | | <p>1.求函数<i>y</i>=-1-1.5sin <i>x</i>的最大值与最小值.</p> |
| | | <p>2.求函数<i>y</i>=3-2sin <i>x</i>,<i>x</i>∈<b>R</b>的单调区间.</p> |
| | | <p>3.不求值,利用函数的单调性,比较下列各对正弦值的大小.</p> |
| | | <p>(1) sin 500°与sin 140°;</p> |
| | | <p> |
| | | (2) |
| | | <math display="0"> |
| | | <p class="p-btn" > |
| | | <span> |
| | | (2)<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>6</mn> |
| | | <mi>π</mi> |
| | | <mn>9</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>6</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>7</mn> |
| | | <mi>π</mi> |
| | | <mn>10</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>. |
| | | </p> |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(40)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <div v-if="isShowAnswer40" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(2) 因为 <math display="0"> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>9</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>10</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mn>0</mn> |
| | | </math>, |
| | | </p> |
| | | <p> |
| | | 而<i>y</i>=sin <i>x</i>在<math display="0"> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">[</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>,</mo> |
| | | <mn>0</mn> |
| | | <mo data-mjx-texclass="CLOSE">]</mo> |
| | | </mrow> |
| | | </math>上是增函数,所以 |
| | | </p> |
| | | <math display="block"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>9</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo><</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>10</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 193 --> |
| | | <div class="page-box hidePage" page="200"></div> |
| | | |
| | | <!-- 194 --> |
| | | <div class="page-box" page="201"> |
| | | <div v-if="showPageList.indexOf(201) > -1"> |
| | | <ul class="page-header-odd fl al-end"> |
| | | <li>194</li> |
| | | <li>数学.基础模块</li> |
| | | <li>上册</li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | | <div class="bj"> |
| | | <examinations :cardList="questionData[201] ? questionData[201][1] : []" |
| | | sourceType="json" inputBc="#d3edfa" v-if="questionData"></examinations> |
| | | </div> |
| | | <h3 id="c060">习题5.6<span class="fontsz2">>>></span></h3> |
| | | <div class="bj"> |
| | | <examinations :cardList="questionData[201] ? questionData[201][2] : []" |
| | | sourceType="json" inputBc="#d3edfa" v-if="questionData"></examinations> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | <!-- 195 --> |
| | | <div class="page-box" page="202"> |
| | | <div v-if="showPageList.indexOf(202) > -1"> |
| | |
| | | <h2 id="b036"> |
| | | 5.7 余弦函数的图像和性质<span class="fontsz1">>>>>>>>></span> |
| | | </h2> |
| | | <h3 id="c061">5.7.1 余弦函数的图像<span class="fontsz2">>>></span></h3> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/wttc.jpg" /></p> |
| | | <h3 id="c061"> |
| | | 5.7.1 余弦函数的图像<span class="fontsz2">>>></span> |
| | | </h3> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/wttc.jpg" /> |
| | | </p> |
| | | <p> |
| | | 我们学习了正弦函数的图像和性质,你能用类似的方法绘制出余弦函数的图像,并根据图像研究它的性质吗? |
| | | </p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /> |
| | | </p> |
| | | <p>根据诱导公式可知,</p> |
| | | <p class="center">cos(<i>x</i>+2π)=cos <i>x</i>.</p> |
| | | <p> |
| | |
| | | <i>x</i>的各个值并填入表中. |
| | | </p> |
| | | <p class="img">表5-9</p> |
| | | <p class="center"><img class="img-a" alt="" src="../../assets/images/0206-1.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0206-1.jpg" /> |
| | | </p> |
| | | <p> |
| | | 其次,描点连线.根据表中数值描点,用光滑的曲线把各点连接起来,得出图像如图5-30所示. |
| | | </p> |
| | | <p class="center"><img class="img-d" alt="" src="../../assets/images/0206-2.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-d" alt="" src="../../assets/images/0206-2.jpg" /> |
| | | </p> |
| | | <p class="img">图5-30</p> |
| | | <p> |
| | | 最后,利用余弦函数的周期性,把<i>y</i>=cos |
| | |
| | | <li>上册</li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0207-1.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-b" alt="" src="../../assets/images/0207-1.jpg" /> |
| | | </p> |
| | | <p class="img">图5-31</p> |
| | | <div class="bk"> |
| | | <div class="bj1"> |
| | |
| | | </math>个单位长度即可得到余弦函数的图像,如图5-32所示. |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0207-4.jpg" /> |
| | | <img class="img-b" alt="" src="../../assets/images/0207-4.jpg" /> |
| | | </p> |
| | | <p class="img">图5-32</p> |
| | | </div> |
| | | <p><b>例</b> 用“五点法”画出下列函数在区间[0,2π]内的简图.</p> |
| | | <p>(1) <i>y</i>=2cos <i>x</i>;(2) <i>y</i>=-1+cos <i>x</i>.</p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) 列表(表5-10). |
| | | <p class="p-btn" > |
| | | <span>(1) <i>y</i>=2cos <i>x</i>;</span> |
| | | <span class="btn-box" @click="hadleAnswer(41)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p class="img">表5-10</p> |
| | | <p class="center"><img class="img-a" alt="" src="../../assets/images/0207-5.jpg" /></p> |
| | | <p class="center"><img class="img-f" alt="" src="../../assets/images/0207-6.jpg" /></p> |
| | | <p class="img">图5-33</p> |
| | | <p>描点连线得<i>y</i>=2cos <i>x</i>在区间[0,2π]</p> |
| | | <p>内的简图,如图5-33所示.</p> |
| | | <p class="p-btn" > |
| | | <span>(2) <i>y</i>=-1+cos <i>x</i>.</span> |
| | | <span class="btn-box" @click="hadleAnswer(42)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <iframe src="https://www.geogebra.org/calculator" frameborder="0" class="iframe-box"></iframe> |
| | | <div v-if="isShowAnswer41" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) 列表(表5-10). |
| | | </p> |
| | | <p class="img">表5-10</p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0207-5.jpg" /> |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-f" alt="" src="../../assets/images/0207-6.jpg" /> |
| | | </p> |
| | | <p class="img">图5-33</p> |
| | | <p>描点连线得<i>y</i>=2cos <i>x</i>在区间[0,2π]</p> |
| | | <p>内的简图,如图5-33所示.</p> |
| | | </div> |
| | | <div v-if="isShowAnswer42" > |
| | | <p>(2) 列表(表5-11).</p> |
| | | <p class="img">表5-11</p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0208-1.jpg" /> |
| | | </p> |
| | | <p> |
| | | 描点连线得<i>y</i>=-1+cos |
| | | <i>x</i>在区间[0,2π]内的简图,如图5-34所示. |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-d" alt="" src="../../assets/images/0208-2.jpg" /> |
| | | </p> |
| | | <p class="img">图5-34</p> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 197 --> |
| | | <div class="page-box" page="204"> |
| | | <div v-if="showPageList.indexOf(204) > -1"> |
| | |
| | | </li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <p>(2) 列表(表5-11).</p> |
| | | <p class="img">表5-11</p> |
| | | <p class="center"><img class="img-a" alt="" src="../../assets/images/0208-1.jpg" /></p> |
| | | <p> |
| | | 描点连线得<i>y</i>=-1+cos <i>x</i>在区间[0,2π]内的简图,如图5-34所示. |
| | | |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0208-2.jpg" /></p> |
| | | <p class="img">图5-34</p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /></p> |
| | | <div class="bj"> |
| | | <p> |
| | | 完成下表(表5-12),利用“五点法”画出<i>y</i>=1-cos |
| | | <i>x</i>在区间[0,2π]内的简图,并说明<i>y</i>=1-cos |
| | | <i>x</i>的图像与<i>y</i>=cos <i>x</i>的图像的区别和联系. |
| | | </p> |
| | | <p class="img">表5-12</p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0208-3.jpg" /> |
| | | </p> |
| | | <fillInTable :queryData="queryDataTwo" /> |
| | | <p> |
| | | 对比<i>y</i>=cos <i>x</i>的图像,<i>y</i>=1-cos |
| | | <i>x</i>图像是将<i>y</i>=cos <i>x</i>的图像通过____变化而得到的. |
| | | <i>x</i>图像是将<i>y</i>=cos <i>x</i>的图像通过 |
| | | <input type="text" class="input-table" /> |
| | | 变化而得到的. |
| | | <span class="btn-box" @click="isShowAnswer = !isShowAnswer" > |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-d" alt="" src="../../assets/images/0208-4.jpg" /> |
| | | <p class="table-answer-box" v-if="isShowAnswer"> |
| | | 答案:翻转和平移 |
| | | </p> |
| | | <paint |
| | | :page="204" |
| | | :canvasHeight="200" |
| | | :imgUrl="this.config.activeBook.resourceUrl + '/images/0208-4.jpg'" |
| | | /> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 198 --> |
| | | <div class="page-box" page="205"> |
| | | <div v-if="showPageList.indexOf(205) > -1"> |
| | |
| | | <li>上册</li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <h3 id="c062">5.7.2 余弦函数的性质<span class="fontsz2">>>></span></h3> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /></p> |
| | | <h3 id="c062"> |
| | | 5.7.2 余弦函数的性质<span class="fontsz2">>>></span> |
| | | </h3> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/cxgk.jpg" /> |
| | | </p> |
| | | <p> |
| | | 通过观察<i>y</i>=cos <i>x</i>的图像可知,余弦函数<i>y</i>=cos |
| | | <i>x</i>的性质有: |
| | |
| | | </p> |
| | | <p>5.单调性.</p> |
| | | <p> |
| | | <i>y</i>=cos <i>x</i>在区间[0,π]上是减函数,在[π,2π]上是增函数. |
| | | <i>y</i>=cos |
| | | <i>x</i>在区间[0,π]上是减函数,在[π,2π]上是增函数. |
| | | </p> |
| | | <p> |
| | | 余弦函数<i>y</i>=cos |
| | | <i>x</i>在每一个区间[2<i>k</i>π,2<i>k</i>π+π](<i>k</i>∈<b>Z</b>)上都是减函数,其值由1减小到-1;在每一个区间[2<i>k</i>π+π,2<i>k</i>π+2π](<i>k</i>∈<b>Z</b>)上都是增函数,其值由-1增大到1. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>例1</b></span> 求函数<i>y</i>=-1+cos <i>x</i>的最大值、最小值、最小正周期及值域. |
| | | <p class="p-btn" > |
| | | <span><span class="zt-ls"><b>例1</b></span> 求函数<i>y</i>=-1+cos <i>x</i>的最大值、最小值、最小正周期及值域.</span> |
| | | <span class="btn-box" @click="hadleAnswer(43)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | 当<i>x</i>=2<i>k</i>π(<i>k</i>∈<b>Z</b>)时,函数<i>y</i>=-1+cos |
| | | <i>x</i>的最大值为<i>y</i>=1-1=0; |
| | | </p> |
| | | <p> |
| | | 当<i>x</i>=2<i>k</i>π+π(<i>k</i>∈<i>Z</i>)时,函数<i>y</i>=-1+cos |
| | | <i>x</i>的最小值为<i>y</i>=-1-1=-2; |
| | | </p> |
| | | <p> |
| | | 函数<i>y</i>=-1+cos <i>x</i>的最小正周期为2π;函数<i>y</i>=-1+cos |
| | | <i>x</i>的值域为[-2,0]. |
| | | </p> |
| | | <div v-if="isShowAnswer43" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | 当<i>x</i>=2<i>k</i>π(<i>k</i>∈<b>Z</b>)时,函数<i>y</i>=-1+cos |
| | | <i>x</i>的最大值为<i>y</i>=1-1=0; |
| | | </p> |
| | | <p> |
| | | 当<i>x</i>=2<i>k</i>π+π(<i>k</i>∈<i>Z</i>)时,函数<i>y</i>=-1+cos |
| | | <i>x</i>的最小值为<i>y</i>=-1-1=-2; |
| | | </p> |
| | | <p> |
| | | 函数<i>y</i>=-1+cos <i>x</i>的最小正周期为2π;函数<i>y</i>=-1+cos |
| | | <i>x</i>的值域为[-2,0]. |
| | | </p> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | |
| | | <p><span>199</span></p> |
| | | </li> |
| | | </ul> |
| | | |
| | | <div class="padding-116"> |
| | | <div class="bk-hzjl"> |
| | | <div class="bj1-hzjl"> |
| | |
| | | <img class="img-gn2" alt="" src="../../assets/images/hzjl.jpg" /> |
| | | </p> |
| | | </div> |
| | | <p class="block"> |
| | | 1.<i>y</i>=2cos <i>x</i>与<i>y</i>=cos <i>x</i>的图像有什么关系? |
| | | </p> |
| | | <p class="block"> |
| | | 2.<i>y</i>=-1+cos <i>x</i>与<i>y</i>=cos <i>x</i>的图像有什么关系? |
| | | </p> |
| | | <examinations :cardList="questionData[206] ? questionData[206][1] : []" |
| | | sourceType="json" v-if="questionData"></examinations> |
| | | </div> |
| | | <p> |
| | | <span class="zt-ls"><b>例2</b></span> 不求值,利用余弦函数的单调性,比较下列各对余弦值的大小. |
| | | </p> |
| | | <p> |
| | | (1) |
| | | <math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>6</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </math>与<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <p class="p-btn" > |
| | | <span> |
| | | (1) |
| | | <math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>6</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | </math>;(2) |
| | | <math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>7</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>与<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | </math>与<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>8</mn> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>. |
| | | </math>; |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(44)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) 因为<math display="0"> |
| | | <mi>π</mi> |
| | | <mo><</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>6</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>,而函数<i>y</i>=cos <i>x</i>在<math display="0"> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">[</mo> |
| | | <div v-if="isShowAnswer44" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) 因为<math display="0"> |
| | | <mi>π</mi> |
| | | <mo>,</mo> |
| | | <mo><</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>6</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">]</mo> |
| | | </mrow> |
| | | </math>上是增函数,所以 |
| | | </p> |
| | | <math display="block"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>6</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | </math>,而函数<i>y</i>=cos <i>x</i>在<math display="0"> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">[</mo> |
| | | <mi>π</mi> |
| | | <mo>,</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">]</mo> |
| | | </mrow> |
| | | </math>上是增函数,所以 |
| | | </p> |
| | | <math display="block"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>6</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </math> |
| | | <p> |
| | | (2)<math display="0"> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </math> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span> |
| | | (2) |
| | | <math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>7</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>与<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>8</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>. |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(45)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <div v-if="isShowAnswer45" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(2)<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>7</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>7</mn> |
| | | </mfrac> |
| | | </math>,<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>8</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>8</mn> |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | 因为<math display="0"> |
| | | <mn>0</mn> |
| | | <mo><</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>8</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>7</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>,而函数<i>y</i>=cos <i>x</i>在0,<math display="0"> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">[</mo> |
| | | <mn>0</mn> |
| | | <mo>,</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">]</mo> |
| | | </mrow> |
| | | </math>上是减函数,所以<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>7</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>8</mn> |
| | | </mfrac> |
| | | </math>,即 |
| | | </p> |
| | | <math display="block"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>7</mn> |
| | | </mfrac> |
| | | </math>,<math display="0"> |
| | | <mo><</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>8</mn> |
| | | </mfrac> |
| | | </math>. |
| | | <mo>.</mo> |
| | | </math> |
| | | </div> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | | <p> |
| | | 因为<math display="0"> |
| | | <mn>0</mn> |
| | | <mo><</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>8</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>7</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>,而函数<i>y</i>=cos <i>x</i>在0,<math display="0"> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">[</mo> |
| | | <mn>0</mn> |
| | | <mo>,</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">]</mo> |
| | | </mrow> |
| | | </math>上是减函数,所以<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>7</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>8</mn> |
| | | </mfrac> |
| | | </math>,即 |
| | | </p> |
| | | <math display="block"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>7</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo><</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>8</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>.</mo> |
| | | </math> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /></p> |
| | | <div class="bj"> |
| | | <p> |
| | | 1.(1) 函数<math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <mn>1</mn> |
| | | <mo>+</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | </math>的最大值为____,最小值为____,最小正周期为____; |
| | | </p> |
| | | <p>(2) 函数<i>y</i>=1+4cos <i>x</i>的最大值为____,最小值为____.</p> |
| | | <p>2.比较大小.</p> |
| | | <p> |
| | | (1) cos 157°____cos 160°;(2) |
| | | <math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>______<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>. |
| | | </p> |
| | | <p>3.下列等式是否成立?并说明理由.</p> |
| | | <p>(1) cos<sup>2</sup><i>x</i>=1;(2) 2cos <i>x</i>=3.</p> |
| | | <p> |
| | | 4.求使下列函数取得最大值、最小值的<i>x</i>的集合,并求出这个函数的最大值、最小值. |
| | | </p> |
| | | <p> |
| | | (1) <i>y</i>=-3cos <i>x</i>;(2) |
| | | <math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <mn>4</mn> |
| | | <mo>+</mo> |
| | | <mfrac> |
| | | <mn>5</mn> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | </math>. |
| | | </p> |
| | | <examinations :cardList="questionData[206] ? questionData[206][2] : []" |
| | | sourceType="json" inputBc="#d3edfa" v-if="questionData"></examinations> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 200 --> |
| | | <div class="page-box" page="207"> |
| | | <div v-if="showPageList.indexOf(207) > -1"> |
| | |
| | | <div class="padding-116"> |
| | | <h3 id="c063">习题5.7<span class="fontsz2">>>></span></h3> |
| | | <div class="bj"> |
| | | <p> |
| | | <span class="bj-sp"><b>水平一</b></span> |
| | | </p> |
| | | <p>1.比较大小.</p> |
| | | <p> |
| | | (1) cos 153°____cos 173°;(2) |
| | | <math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>8</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>7</mn> |
| | | </mfrac> |
| | | </math>____<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>9</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>7</mn> |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p>2.(1) 函数<i>y</i>=3cos <i>x</i>的最大值为____,最小值为____;</p> |
| | | <p>(2) 函数<i>y</i>=-0.5cos <i>x</i>的最大值为____,最小值为____.</p> |
| | | <p> |
| | | 3.函数<i>y</i>=1+3cos |
| | | <i>x</i>,<i>x</i>∈0,2π,当<i>x</i>=____时,<i>y</i>取最大值;当<i>x</i>=____时,<i>y</i>取最小值. |
| | | </p> |
| | | <p>4.求函数<i>y</i>=2+cos <i>x</i>,<i>x</i>∈0,2π的单调区间.</p> |
| | | <p>5.利用“五点法”画出函数<i>y</i>=-4cos <i>x</i>在区间0,2π内的图像.</p> |
| | | <p> |
| | | <span class="bj-sp"><b>水平二</b></span> |
| | | </p> |
| | | <p>1.求函数<i>y</i>=|cos <i>x</i>的最小正周期.</p> |
| | | <p> |
| | | 2.求函数<math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>2</mn> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mn>1</mn> |
| | | <mo>+</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | </math>的定义域. |
| | | </p> |
| | | <p>3.不求值,利用函数的单调性,比较下列各对函数值的大小.</p> |
| | | <p> |
| | | (1) |
| | | <math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>23</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>与<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>17</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>; |
| | | </p> |
| | | <p> |
| | | (2) |
| | | <math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>7</mn> |
| | | </mfrac> |
| | | </math>与<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>. |
| | | </p> |
| | | <examinations :cardList="questionData[207]" sourceType="json" inputBc="#d3edfa" |
| | | v-if="questionData"></examinations> |
| | | </div> |
| | | <h2 id="b037"> |
| | | 5.8 已知三角函数值,求指定范围的角<span class="fontsz1">>>>>>>>></span> |
| | |
| | | <h3 id="c064"> |
| | | 5.8.1 已知特殊三角函数值求角<span class="fontsz2">>>></span> |
| | | </h3> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/wttc.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/wttc.jpg" /> |
| | | </p> |
| | | <p> |
| | | 如果<math display="0"> |
| | | <mi>x</mi> |
| | |
| | | </li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /></p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /> |
| | | </p> |
| | | <p> |
| | | 由<math display="0"> |
| | | <mi>sin</mi> |
| | |
| | | </mfrac> |
| | | </math>与正弦曲线<i>y</i>=sin <i>x</i>交点所对应的<i>x</i>的值. |
| | | </p> |
| | | <p class="center"><img class="img-a" alt="" src="../../assets/images/0212-9.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0212-9.jpg" /> |
| | | </p> |
| | | <p class="img">图5-35</p> |
| | | <p> |
| | | 观察图像可知,直线<math display="0"> |
| | |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>例1</b></span> 已知<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例1</b></span> 已知<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>2</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>,且<i>x</i>∈[0,2π] ,求<i>x</i>的值. |
| | | </mfrac> |
| | | </math>,且<i>x</i>∈[0,2π] ,求<i>x</i>的值. |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(46)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p> |
| | | <p v-if="isShowAnswer46"> |
| | | <span class="zt-ls"><b>解</b></span> 因为<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 202 --> |
| | | <div class="page-box" page="209"> |
| | | <div v-if="showPageList.indexOf(209) > -1"> |
| | |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>例2</b></span> 已知<math display="0"> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mi>x</mi> |
| | | <mo>≠</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mi>k</mi> |
| | | <mi>π</mi> |
| | | <mo>,</mo> |
| | | <mi>k</mi> |
| | | <mo>∈</mo> |
| | | <mrow> |
| | | <mi mathvariant="bold">Z</mi> |
| | | </mrow> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>,且0°≤<i>x</i>≤360°,求<i>x</i>的值. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 因为<math display="0"> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mo>></mo> |
| | | <mn>0</mn> |
| | | </math>,所以<i>x</i>是第一或第三象限角. |
| | | </p> |
| | | <p> |
| | | 由<math display="0"> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mn>60</mn> |
| | | <mrow> |
| | | <mo>°</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | </math>可知,符合条件的第一象限角是<i>x</i>=60°. |
| | | </p> |
| | | <p> |
| | | 又因为<math display="0"> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mn>180</mn> |
| | | <mrow> |
| | | <mo>°</mo> |
| | | </mrow> |
| | | <mo>+</mo> |
| | | <mn>60</mn> |
| | | <mrow> |
| | | <mo>°</mo> |
| | | </mrow> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mn>60</mn> |
| | | <mrow> |
| | | <mo>°</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | </math>, |
| | | </p> |
| | | <p>所以符合条件的第三象限角是<i>x</i>=180°+60°=240°.</p> |
| | | <p>所以<i>x</i>=60°或<i>x</i>=240°.</p> |
| | | <div class="bk"> |
| | | <div class="bj1"> |
| | | <p class="left"> |
| | | <img class="img-gn1" alt="" src="../../assets/images/tbts.jpg" /> |
| | | </p> |
| | | </div> |
| | | <p class="block"> |
| | | 已知三角函数值,求给定范围的角<i>x</i>的值,其基本步骤如下. |
| | | </p> |
| | | <p class="block"> |
| | | (1) 根据已知三角函数值的符号,判定角<i>x</i>所在的象限; |
| | | </p> |
| | | <p class="block">(2) 求出满足三角函数值的锐角<i>x</i>′;</p> |
| | | <p class="block"> |
| | | (3) |
| | | 根据<i>x</i>所在的象限和诱导公式,写出满足题目给定范围的<i>x</i>的值. |
| | | </p> |
| | | </div> |
| | | <p> |
| | | <span class="zt-ls"><b>例3</b></span> 已知<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>,且<i>x</i>∈[-π,π],求<i>x</i>的值. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 因为<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>></mo> |
| | | <mn>0</mn> |
| | | </math>,所以<i>x</i>是第一或第四象限角. |
| | | </p> |
| | | <p> |
| | | 满足<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>的锐角是<math display="0"> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math>,所以符合条件的第一象限角是<math display="0"> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | 因为<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>, |
| | | </p> |
| | | <p> |
| | | 所以符合条件的第四象限角是<math display="0"> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | 所以<math display="0"> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math>或<math display="0"> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /></p> |
| | | <div class="bj"> |
| | | <p> |
| | | 1.已知<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>2</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>,且<i>x</i>∈[0,2π],则<i>x</i>的值为____. |
| | | </p> |
| | | <p> |
| | | 2.已知<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>,且<i>x</i>∈[0,2π],则<i>x</i>的值为____. |
| | | </p> |
| | | |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 203 --> |
| | | <div class="page-box" page="210"> |
| | | <div v-if="showPageList.indexOf(210) > -1"> |
| | | <ul class="page-header-box"> |
| | | <li> |
| | | <p>第五单元 三角函数</p> |
| | | </li> |
| | | <li> |
| | | <p><span>203</span></p> |
| | | </li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <div class="bj"> |
| | | <p> |
| | | 3.已知<math display="0"> |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例2</b></span> 已知<math display="0"> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </msqrt> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mi>x</mi> |
| | |
| | | </mrow> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>,且<i>x</i>∈[0,2π],则<i>x</i>的值为____. |
| | | </math>,且0°≤<i>x</i>≤360°,求<i>x</i>的值. |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(47)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <div v-if="isShowAnswer47" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 因为<math display="0"> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mo>></mo> |
| | | <mn>0</mn> |
| | | </math>,所以<i>x</i>是第一或第三象限角. |
| | | </p> |
| | | <p> |
| | | 由<math display="0"> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mn>60</mn> |
| | | <mrow> |
| | | <mo>°</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | </math>可知,符合条件的第一象限角是<i>x</i>=60°. |
| | | </p> |
| | | <p> |
| | | 又因为<math display="0"> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mn>180</mn> |
| | | <mrow> |
| | | <mo>°</mo> |
| | | </mrow> |
| | | <mo>+</mo> |
| | | <mn>60</mn> |
| | | <mrow> |
| | | <mo>°</mo> |
| | | </mrow> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mn>60</mn> |
| | | <mrow> |
| | | <mo>°</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | </math>, |
| | | </p> |
| | | <p>所以符合条件的第三象限角是<i>x</i>=180°+60°=240°.</p> |
| | | <p>所以<i>x</i>=60°或<i>x</i>=240°.</p> |
| | | </div> |
| | | <div class="bk"> |
| | | <div class="bj1"> |
| | | <p class="left"> |
| | | <img class="img-gn1" alt="" src="../../assets/images/tbts.jpg" /> |
| | | </p> |
| | | </div> |
| | | <p class="block"> |
| | | 已知三角函数值,求给定范围的角<i>x</i>的值,其基本步骤如下. |
| | | </p> |
| | | <p class="block"> |
| | | (1) 根据已知三角函数值的符号,判定角<i>x</i>所在的象限; |
| | | </p> |
| | | <p class="block">(2) 求出满足三角函数值的锐角<i>x</i>′;</p> |
| | | <p class="block"> |
| | | (3) |
| | | 根据<i>x</i>所在的象限和诱导公式,写出满足题目给定范围的<i>x</i>的值. |
| | | </p> |
| | | </div> |
| | | <h3 id="c065"> |
| | | 5.8.2 已知任意三角函数值求角<span class="fontsz2">>>></span> |
| | | </h3> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/wttc.jpg" /></p> |
| | | <p> |
| | | 我们已经探究了已知特殊的三角函数值求角的方法,而对于不是特殊的三角函数值,又该如何求角呢? |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例3</b></span> 已知<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>,且<i>x</i>∈[-π,π],求<i>x</i>的值. |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(48)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /></p> |
| | | <p> |
| | | 根据已知特殊的三角函数值求角的方法,借助计算工具,可以解决已知任意三角函数值求角的问题. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>例1</b></span> 已知<math display="0"> |
| | | <mi>α</mi> |
| | | <mo>∈</mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">[</mo> |
| | | <div v-if="isShowAnswer48" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 因为<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>></mo> |
| | | <mn>0</mn> |
| | | </math>,所以<i>x</i>是第一或第四象限角. |
| | | </p> |
| | | <p> |
| | | 满足<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>的锐角是<math display="0"> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math>,所以符合条件的第一象限角是<math display="0"> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | 因为<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>, |
| | | </p> |
| | | <p> |
| | | 所以符合条件的第四象限角是<math display="0"> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>,</mo> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | 所以<math display="0"> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">]</mo> |
| | | </mrow> |
| | | </math>,求<i>α</i>的值.(结果精确到0.000 1) |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 因为<math display="0"> |
| | | <mi>α</mi> |
| | | <mo>∈</mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">[</mo> |
| | | </math>或<math display="0"> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>,</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">]</mo> |
| | | </mrow> |
| | | </math>,所以<i>α</i>在<i>y</i>=sin <i>α</i>的一个单调区间内,这时使sin |
| | | <i>α</i>=0.943 7的角<i>α</i>的值是唯一的. |
| | | </math>. |
| | | </p> |
| | | </div> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | | <p> |
| | | 先将科学计算器的精确度设置为0.000 |
| | | 1,再将科学计算器设置为弧度计算模式,然后依次按键: |
| | | </p> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0214-4.jpg" /></p> |
| | | <p>结果显示:</p> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0214-5.jpg" /></p> |
| | | <p>所以 <i>α</i>≈1.233 6.</p> |
| | | <p> |
| | | <span class="zt-ls"><b>例2</b></span> 已知cos <i>α</i>=0.694 |
| | | 3,0°≤<i>α</i>≤180°,求<i>α</i>的值.(结果精确到0.000 1) |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 因为0°≤<i>α</i>≤180°,所以<i>α</i>在<i>y</i>=cos |
| | | <i>α</i>的一个单调区间内,这时使cos <i>α</i>=0.694 |
| | | 3的角<i>α</i>的值是唯一的. |
| | | </p> |
| | | <div class="bj"> |
| | | <examinations :cardList="questionData[209]" sourceType="json" inputBc="#d3edfa" |
| | | v-if="questionData"></examinations> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | <!-- 204 --> |
| | | <div class="page-box" page="211"> |
| | | <div v-if="showPageList.indexOf(211) > -1"> |
| | | <ul class="page-header-odd fl al-end"> |
| | | <li>204</li> |
| | | <li>数学.基础模块</li> |
| | | <li>上册</li> |
| | | </ul> |
| | | |
| | | <div class="padding-116"> |
| | | <p> |
| | | 先将科学计算器的精确度设置为0.000 |
| | | 1,再将科学计算器设置为角度计算模式,然后依次按键: |
| | | </p> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0215-1.jpg" /></p> |
| | | <p>结果显示:</p> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0215-2.jpg" /></p> |
| | | <p>所以<i>α</i>≈46.028 5°.</p> |
| | | <p> |
| | | 注意:应当区分所给条件中角的单位是角度还是弧度.如果是角度,计算时应用角度计算模式; |
| | | 如果是弧度,计算时应用弧度计算模式. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>例3</b></span> 已知tan <i>α</i>=-2.747 0,<math display="0"> |
| | | <mi>α</mi> |
| | | <mo>∈</mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>,</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>,求<i>α</i>的值.(结果精确到0.000 1) |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 因为<math display="0"> |
| | | <mi>α</mi> |
| | | <mo>∈</mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>,</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>,所以<i>α</i>在<i>y</i>=tan <i>α</i>的一个单调区间内,这时使tan |
| | | <i>α</i>=-2.747 0的角<i>α</i>的值是唯一的. |
| | | </p> |
| | | <p> |
| | | 先将科学计算器的精确度设置为0.000 |
| | | 1,再将科学计算器设置为弧度计算模式,然后依次按键: |
| | | </p> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0215-5.jpg" /></p> |
| | | <p>结果显示:</p> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0215-6.jpg" /></p> |
| | | <p>所以 <i>α</i>≈-1.221 7.</p> |
| | | <p> |
| | | <span class="zt-ls"><b>例4</b></span> 已知sin <i>α</i>=-0.857 |
| | | 2,<i>α</i>∈[0,2π],求<i>α</i>的值.(结果精确到0.000 1) |
| | | </p> |
| | | <p class="block"> |
| | | <span class="zt-ls2"><b>分析</b></span> 因为sin <i>α</i>=-0.857 |
| | | 2<0,在[0,2π]范围内有两个<i>α</i>值满足条件,它们分别位于第三象限和第四象限,即<i>α</i>在[π,2π]范围内.可用科学计算器先求出sin |
| | | <i>α</i>=0.857 2所对应的锐角,再利用诱导公式求出所求的角. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 先将科学计算器的精确度设置为0.000 |
| | | 1,再将科学计算器设置为弧度计算模式,然后依次按键: |
| | | </p> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0215-7.jpg" /></p> |
| | | <p>结果显示:</p> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0215-8.jpg" /></p> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 205 --> |
| | | <div class="page-box" page="212"> |
| | | <div v-if="showPageList.indexOf(212) > -1"> |
| | | <!-- 203 --> |
| | | <div class="page-box" page="210"> |
| | | <div v-if="showPageList.indexOf(210) > -1"> |
| | | <ul class="page-header-box"> |
| | | <li> |
| | | <p>第五单元 三角函数</p> |
| | | </li> |
| | | <li> |
| | | <p><span>205</span></p> |
| | | <p><span>203</span></p> |
| | | </li> |
| | | </ul> |
| | | |
| | | <div class="padding-116"> |
| | | <p>即</p> |
| | | <p class="center">sin 1.029 8≈0.857 2.</p> |
| | | <p>因为</p> |
| | | <p class="center">sin(π+1.029 8)=-sin 1.029 8≈-0.857 2,</p> |
| | | <p>所以符合条件的第三象限角是π+1.029 8≈4.171 4.</p> |
| | | <p>因为</p> |
| | | <p class="center">sin(2π-1.029 8)=-sin 1.029 8≈-0.857 2,</p> |
| | | <p>所以符合条件的第四象限角是2π-1.029 8≈5.253 4.</p> |
| | | <p> |
| | | 所以满足sin <i>α</i>=-0.857 |
| | | 2,<i>α</i>∈[0,2π]的角<i>α</i>的集合为{4.171 4,5.253 4}. |
| | | <h3 id="c065"> |
| | | 5.8.2 已知任意三角函数值求角<span class="fontsz2">>>></span> |
| | | </h3> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/wttc.jpg" /> |
| | | </p> |
| | | <p class="left"><img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /></p> |
| | | <div class="bj"> |
| | | <p>借助科学计算器,求出下列指定范围内的角.(结果精确到0.000 1)</p> |
| | | <p> |
| | | 1.已知<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>β</mi> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mn>7</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mn>0</mn> |
| | | </math>,<i>β</i>∈[0,π],则<i>β</i>的值为____. |
| | | </p> |
| | | <p> |
| | | 2.已知tan<i>γ</i>=-0.234 5,-90°<<i>γ</i><90°,则<i>γ</i>的值为____. |
| | | </p> |
| | | <p> |
| | | 3.已知sin <i>α</i>=0.973 4,0°≤<i>α</i>≤360°,则<i>α</i>的值为____. |
| | | </p> |
| | | <p> |
| | | 4.已知cos <i>β</i>=-0.202 8,<i>β</i>∈[-π,π],则<i>β</i>的值为____. |
| | | </p> |
| | | </div> |
| | | <h3 id="c066">习题5.8<span class="fontsz2">>>></span></h3> |
| | | <div class="bj"> |
| | | <p> |
| | | <span class="bj-sp"><b>水平一</b></span> |
| | | </p> |
| | | <p> |
| | | 1.已知<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>,<math display="0"> |
| | | <mi>x</mi> |
| | | <p> |
| | | 我们已经探究了已知特殊的三角函数值求角的方法,而对于不是特殊的三角函数值,又该如何求角呢? |
| | | </p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/fxlj.jpg" /> |
| | | </p> |
| | | <p> |
| | | 根据已知特殊的三角函数值求角的方法,借助计算工具,可以解决已知任意三角函数值求角的问题. |
| | | </p> |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例1</b></span> 已知<math display="0"> |
| | | <mi>α</mi> |
| | | <mo>∈</mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">[</mo> |
| | |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">]</mo> |
| | | </mrow> |
| | | </math>,则<i>x</i>的值为____. |
| | | </p> |
| | | </math>,求<i>α</i>的值.(结果精确到0.000 1) |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(49)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <iframe src="https://www.geogebra.org/scientific" frameborder="0" class="iframe-box"></iframe> |
| | | <div v-if="isShowAnswer49" > |
| | | <p> |
| | | 2.已知<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <span class="zt-ls"><b>解</b></span> 因为<math display="0"> |
| | | <mi>α</mi> |
| | | <mo>∈</mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">[</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>,0°≤<i>x</i>≤180°,则<i>x</i>的值为____. |
| | | </mfrac> |
| | | <mo>,</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">]</mo> |
| | | </mrow> |
| | | </math>,所以<i>α</i>在<i>y</i>=sin <i>α</i>的一个单调区间内,这时使sin |
| | | <i>α</i>=0.943 7的角<i>α</i>的值是唯一的. |
| | | </p> |
| | | <p> |
| | | 3.已知<math display="0"> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | </math>,-90°<<i>x</i><90°,则<i>x</i>的值为____. |
| | | 先将科学计算器的精确度设置为0.000 |
| | | 1,再将科学计算器设置为弧度计算模式,然后依次按键: |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0214-4.jpg" /> |
| | | </p> |
| | | <p>结果显示:</p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0214-5.jpg" /> |
| | | </p> |
| | | <p>所以 <i>α</i>≈1.233 6.</p> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例2</b></span> 已知cos <i>α</i>=0.694 |
| | | 3,0°≤<i>α</i>≤180°,求<i>α</i>的值.(结果精确到0.000 1) |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(50)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <div v-if="isShowAnswer50" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 因为0°≤<i>α</i>≤180°,所以<i>α</i>在<i>y</i>=cos |
| | | <i>α</i>的一个单调区间内,这时使cos <i>α</i>=0.694 |
| | | 3的角<i>α</i>的值是唯一的. |
| | | </p> |
| | | <p> |
| | | 4.借助科学计算器,求适合下列各式中的<i>x</i>(0≤<i>x</i><2π)的值的集合.(结果精确到0.000 |
| | | 1) |
| | | 先将科学计算器的精确度设置为0.000 |
| | | 1,再将科学计算器设置为角度计算模式,然后依次按键: |
| | | </p> |
| | | <p>(1) sin <i>x</i>=0.318 5;(2) cos <i>x</i>=-0.789 0.</p> |
| | | <p>5.求适合下列各式中的<i>x</i>(-π≤<i>x</i>≤π)的值的集合.</p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0215-1.jpg" /> |
| | | </p> |
| | | <p>结果显示:</p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0215-2.jpg" /> |
| | | </p> |
| | | <p>所以<i>α</i>≈46.028 5°.</p> |
| | | <p> |
| | | (1) |
| | | <math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>;(2) cos <i>x</i>=-0.5;(3) tan <i>x</i>=-1. |
| | | 注意:应当区分所给条件中角的单位是角度还是弧度.如果是角度,计算时应用角度计算模式; |
| | | 如果是弧度,计算时应用弧度计算模式. |
| | | </p> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | <!-- 204 --> |
| | | <div class="page-box" page="211"> |
| | | <div v-if="showPageList.indexOf(211) > -1"> |
| | | <ul class="page-header-odd fl al-end"> |
| | | <li>204</li> |
| | | <li>数学.基础模块</li> |
| | | <li>上册</li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例3</b></span> 已知tan <i>α</i>=-2.747 0,<math display="0"> |
| | | <mi>α</mi> |
| | | <mo>∈</mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>,</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>,求<i>α</i>的值.(结果精确到0.000 1) |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(51)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <iframe src="https://www.geogebra.org/scientific" frameborder="0" class="iframe-box"></iframe> |
| | | <div v-if="isShowAnswer51" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 因为<math display="0"> |
| | | <mi>α</mi> |
| | | <mo>∈</mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>,</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>,所以<i>α</i>在<i>y</i>=tan <i>α</i>的一个单调区间内,这时使tan |
| | | <i>α</i>=-2.747 0的角<i>α</i>的值是唯一的. |
| | | </p> |
| | | <p> |
| | | 先将科学计算器的精确度设置为0.000 |
| | | 1,再将科学计算器设置为弧度计算模式,然后依次按键: |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0215-5.jpg" /> |
| | | </p> |
| | | <p>结果显示:</p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0215-6.jpg" /> |
| | | </p> |
| | | <p>所以 <i>α</i>≈-1.221 7.</p> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例4</b></span> 已知sin <i>α</i>=-0.857 |
| | | 2,<i>α</i>∈[0,2π],求<i>α</i>的值.(结果精确到0.000 1) |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(52)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | <span class="btn-box" @click="openDialog(thinkOne)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.545" height="18.112" viewBox="0 0 20.545 22.112"> |
| | | <path class="a" |
| | | d="M3771.2-14311.889a2.356,2.356,0,0,1-1.727-.626c-.027-.054-.053-.1-.079-.148l0-.007c-.123-.224-.2-.371-.076-.629a.869.869,0,0,1,.784-.471.205.205,0,0,1,.158.079.205.205,0,0,0,.158.079.187.187,0,0,0,.038.1.143.143,0,0,0,.117.05h.158a.573.573,0,0,0,.471.158,2.2,2.2,0,0,0,.916-.3l.023-.011a.572.572,0,0,1,.471-.158.575.575,0,0,1,.626.626.526.526,0,0,1,.036.409.664.664,0,0,1-.349.375A3.582,3.582,0,0,1,3771.2-14311.889Zm-1.885-1.723h-.155a.718.718,0,0,1-.784-.63.38.38,0,0,1-.021-.3.976.976,0,0,1,.492-.485l4.86-1.252a1.047,1.047,0,0,1,.784.626c.151.3-.128.61-.471.784l-4.705,1.256Zm-.155-1.885H3769a.716.716,0,0,1-.784-.626c-.149-.3.129-.611.471-.784l4.234-1.1v-.158l-.021.007a7.808,7.808,0,0,1-1.861.31,5.3,5.3,0,0,1-3.137-.942,5.789,5.789,0,0,1-2.666-4.076,6.421,6.421,0,0,1,1.256-5.018,7.038,7.038,0,0,1,2.194-1.568,7.848,7.848,0,0,1,2.666-.472,6.43,6.43,0,0,1,2.979.784,4.958,4.958,0,0,1,2.2,2.194,5.522,5.522,0,0,1,.313,5.177,13.113,13.113,0,0,1-1.256,1.882l-.313.313a2.156,2.156,0,0,0-.78,1.244l0,.012a1.731,1.731,0,0,1-1.727,1.723l-.313.158-3.292.939Zm1.256-6.271v1.256h1.41v-1.256Zm.784-4.234c.718,0,1.1.271,1.1.784a.925.925,0,0,1-.316.783l-.468.156a2.235,2.235,0,0,0-.63.471l-.012.024a2.2,2.2,0,0,0-.3.918v.155h1.1v-.155a1.2,1.2,0,0,1,.313-.629.543.543,0,0,0,.315-.153c.007,0,.315,0,.315-.16a1.226,1.226,0,0,0,.626-.626,2.277,2.277,0,0,0,.313-1.1,1.409,1.409,0,0,0-.626-1.252,2.337,2.337,0,0,0-1.569-.471,2.258,2.258,0,0,0-2.507,2.353l1.252.154A1.121,1.121,0,0,1,3771.2-14326Zm-6.51,9.645a.769.769,0,0,1-.549-.237.772.772,0,0,1-.235-.549.772.772,0,0,1,.235-.548l.939-.939a.781.781,0,0,1,.55-.234.772.772,0,0,1,.547.234.772.772,0,0,1,.238.549.772.772,0,0,1-.238.549l-.939.938A.769.769,0,0,1,3764.686-14316.356Zm13.174-.157a.774.774,0,0,1-.549-.234l-.943-.942a.678.678,0,0,1-.233-.47.678.678,0,0,1,.233-.47.774.774,0,0,1,.549-.234.774.774,0,0,1,.549.234l.942.939a.427.427,0,0,1,.228.324.74.74,0,0,1-.228.618A.774.774,0,0,1,3777.859-14316.514Zm2.9-6.351h-1.414c-.469-.158-.784-.474-.784-.784a.743.743,0,0,1,.784-.784h1.414a.743.743,0,0,1,.784.784A.743.743,0,0,1,3780.761-14322.864Zm-17.566-.158h-1.41c-.469-.157-.784-.473-.784-.784a.743.743,0,0,1,.784-.784h1.41a.743.743,0,0,1,.784.784A.743.743,0,0,1,3763.195-14323.022Zm13.861-5.723a.759.759,0,0,1-.529-.237.776.776,0,0,1-.235-.549.772.772,0,0,1,.235-.549l.939-.938a.44.44,0,0,1,.413-.238.759.759,0,0,1,.529.238.772.772,0,0,1,.235.549.772.772,0,0,1-.235.548l-.942.939A.435.435,0,0,1,3777.055-14328.745Zm-11.429,0a.776.776,0,0,1-.55-.237l-.939-1.1a.678.678,0,0,1-.235-.469.678.678,0,0,1,.235-.47.772.772,0,0,1,.549-.238.772.772,0,0,1,.549.238l.939,1.1a.675.675,0,0,1,.238.47.675.675,0,0,1-.238.47A.767.767,0,0,1,3765.626-14328.745Zm5.724-2.273a.743.743,0,0,1-.784-.785v-1.413c.157-.469.473-.784.784-.784a.743.743,0,0,1,.784.784v1.413A.743.743,0,0,1,3771.35-14331.019Z" |
| | | transform="translate(-3761 14334.001)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <div v-if="isShowAnswer52" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | 先将科学计算器的精确度设置为0.000 |
| | | 1,再将科学计算器设置为弧度计算模式,然后依次按键: |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0215-7.jpg" /> |
| | | </p> |
| | | <p>结果显示:</p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0215-8.jpg" /> |
| | | </p> |
| | | <p>即</p> |
| | | <p class="center">sin 1.029 8≈0.857 2.</p> |
| | | <p>因为</p> |
| | | <p class="center">sin(π+1.029 8)=-sin 1.029 8≈-0.857 2,</p> |
| | | <p>所以符合条件的第三象限角是π+1.029 8≈4.171 4.</p> |
| | | <p>因为</p> |
| | | <p class="center">sin(2π-1.029 8)=-sin 1.029 8≈-0.857 2,</p> |
| | | <p>所以符合条件的第四象限角是2π-1.029 8≈5.253 4.</p> |
| | | <p> |
| | | 所以满足sin <i>α</i>=-0.857 |
| | | 2,<i>α</i>∈[0,2π]的角<i>α</i>的集合为{4.171 4,5.253 4}. |
| | | </p> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | <!-- 205 --> |
| | | <div class="page-box" page="212"> |
| | | <div v-if="showPageList.indexOf(212) > -1"> |
| | | <ul class="page-header-box"> |
| | | <li> |
| | | <p>第五单元 三角函数</p> |
| | | </li> |
| | | <li> |
| | | <p><span>205-206</span></p> |
| | | </li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | | <div class="bj"> |
| | | <examinations :cardList="questionData[212] ? questionData[212][1] : []" |
| | | sourceType="json" inputBc="#d3edfa" v-if="questionData"></examinations> |
| | | </div> |
| | | <h3 id="c066">习题5.8<span class="fontsz2">>>></span></h3> |
| | | <div class="bj"> |
| | | <examinations :cardList="questionData[212] ? questionData[212][2] : []" |
| | | sourceType="json" inputBc="#d3edfa" v-if="questionData"></examinations> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 206 --> |
| | | <div class="page-box" page="213"> |
| | | <div v-if="showPageList.indexOf(213) > -1"> |
| | | <ul class="page-header-odd fl al-end"> |
| | | <li>206</li> |
| | | <li>数学.基础模块</li> |
| | | <li>上册</li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <div class="bj"> |
| | | |
| | | <p> |
| | | <span class="bj-sp"><b>水平二</b></span> |
| | | </p> |
| | | <p> |
| | | 1.借助科学计算器,求适合下列各式中<i>x</i>的值.(结果精确到0.000 1) |
| | | </p> |
| | | <p> |
| | | (1) |
| | | <math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </math>,<math display="0"> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mi>x</mi> |
| | | <mo><</mo> |
| | | <mi>π</mi> |
| | | </math>;(2) |
| | | <math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | </math>,<math display="0"> |
| | | <mi>π</mi> |
| | | <mo><</mo> |
| | | <mi>x</mi> |
| | | <mo><</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>; |
| | | </p> |
| | | <p> |
| | | (3) |
| | | <math display="0"> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math>,<math display="0"> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mi>x</mi> |
| | | <mo><</mo> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | 2.求满足<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mn>2</mn> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>的角<i>x</i>(0°≤<i>x</i>≤180°)的值的集合. |
| | | </p> |
| | | <p> |
| | | 3.借助科学计算器,求出下面指定范围内的角<i>β</i>的值的集合:cos |
| | | 2<i>β</i>=-0.690 9,0°≤<i>β</i>≤180°.(结果精确到0.000 1) |
| | | </p> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | <div class="page-box hidePage" page="213"></div> |
| | | |
| | | <!-- 207 --> |
| | | <div class="page-box" page="214"> |
| | |
| | | </ul> |
| | | |
| | | <div class="padding-116"> |
| | | |
| | | <h2 id="b038">数学园地<span class="fontsz1">>>>>>>>></span></h2> |
| | | <h2 id="b038"> |
| | | 数学园地<span class="fontsz1">>>>>>>>></span> |
| | | </h2> |
| | | <p class="center">三角学在我国的发展</p> |
| | | <p> |
| | | 我国很早就开始了对三角知识的研究.我国古老的数学书籍《周髀算经》一书中,记载了古时候人们计算地面上一点到太阳距离的方法.魏晋时期的著名数学家刘徽在古人“重差术”的基础上,编撰了《海岛算经》一书. |
| | |
| | | <li>上册</li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <h2 id="b039">单元小结<span class="fontsz1">>>>>>>>></span></h2> |
| | | <h2 id="b039"> |
| | | 单元小结<span class="fontsz1">>>>>>>>></span> |
| | | </h2> |
| | | <p class="bj2"><b>学习导图</b></p> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0219-1.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0219-1.jpg" /> |
| | | </p> |
| | | <p class="bj2"><b>学习指导</b></p> |
| | | <p> |
| | | 1.与角<i>α</i>终边相同的角的集合:<i>S</i>={<i>β</i>|<i>β</i>=<i>α</i>+<i>k</i>·2π,<i>k</i>∈<b>Z</b>}. |
| | |
| | | </p> |
| | | <p>6.同角三角函数基本关系式.</p> |
| | | <p> |
| | | (1) 平方关系:sin <sup>2</sup> <i>α</i>+cos <sup>2</sup> <i>α</i>=1; |
| | | (1) 平方关系:sin <sup>2</sup> <i>α</i>+cos <sup>2</sup> |
| | | <i>α</i>=1; |
| | | </p> |
| | | <p> |
| | | (2) 商数关系:<math display="0"> |
| | |
| | | </math>. |
| | | </p> |
| | | <p>7.诱导公式表(<i>k</i>∈<b>Z</b>).</p> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0220-3.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0220-3.jpg" /> |
| | | </p> |
| | | <p>8.正弦函数、余弦函数的图像和性质.</p> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0220-4.jpg" /></p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0220-4.jpg" /> |
| | | </p> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | <!-- 210 --> |
| | | |
| | | <div class="page-box" page="217"> |
| | | <div v-if="showPageList.indexOf(217) > -1"> |
| | | <ul class="page-header-odd fl al-end"> |
| | | <li>210</li> |
| | | <li>210-211</li> |
| | | <li>数学.基础模块</li> |
| | | <li>上册</li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <h2 id="b040">单元检测<span class="fontsz1">>>>>>>>></span></h2> |
| | | <h2 id="b040"> |
| | | 单元检测<span class="fontsz1">>>>>>>>></span> |
| | | </h2> |
| | | <div class="bj"> |
| | | <p> |
| | | <span class="bj-sp"><b>水平一</b></span> |
| | | </p> |
| | | <p>1.选择题.</p> |
| | | <p>(1) 下列正确的是( ).</p> |
| | | <p> |
| | | A.<math display="0"> |
| | | <mn>15</mn> |
| | | <mrow> |
| | | <mo>°</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>11</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | B.<math display="0"> |
| | | <mn>1200</mn> |
| | | <mrow> |
| | | <mo>°</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>21</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | C.<math display="0"> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mn>150</mn> |
| | | <mrow> |
| | | <mo>°</mo> |
| | | </mrow> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | D.<math display="0"> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>7</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>8</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mn>220</mn> |
| | | <mrow> |
| | | <mo>°</mo> |
| | | </mrow> |
| | | </math> |
| | | </p> |
| | | <p>(2) 下列正确的是( ).</p> |
| | | <p>A.cos(-60°)<0</p> |
| | | <p>B.tan 320°>0</p> |
| | | <p> |
| | | C.<math display="0"> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo>></mo> |
| | | <mn>0</mn> |
| | | </math> |
| | | </p> |
| | | <p>D.cos 330°>0</p> |
| | | <p>(3) 下列正确的是( ).</p> |
| | | <p> |
| | | A.<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>7</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>7</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | B.<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>></mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | C.<math display="0"> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>9</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>7</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>></mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>9</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>8</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math> |
| | | </p> |
| | | <p>D.sin 6>sin 7</p> |
| | | <p> |
| | | 2.(1) 在0°~360°范围内,与1 |
| | | 458°角终边相同的角是____,它是第____象限角; |
| | | </p> |
| | | <p> |
| | | (2) 在0°~360°范围内,与-330°角终边相同的角是____,它是第____象限角. |
| | | </p> |
| | | <p>3.计算.</p> |
| | | <p> |
| | | (1) |
| | | <math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>25</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>17</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>+</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>23</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | </math>______; |
| | | </p> |
| | | <p> |
| | | (2) sin <sup>2</sup>150°+2sin 390°+cos |
| | | <sup>2</sup>(-120°)+tan(-60°)= ; |
| | | </p> |
| | | <p>(3) tan1+cos 2+sin 3=______.(使用科学计算器)</p> |
| | | <p> |
| | | 4.已知角<i>α</i>的终边上有一点 <i>P</i>(5,-12),求 sin |
| | | <i>α</i>,cos <i>α</i>,tan <i>α</i>的值. |
| | | </p> |
| | | <p> |
| | | 5.已知<i>α</i>为锐角,且<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </math>,求cos <i>α</i>,tan <i>α</i>的值. |
| | | </p> |
| | | <p> |
| | | 6.已知 <i>tanθ</i>=3,且<i>θ</i>为第三象限角,求sin <i>θ</i>,cos |
| | | <i>θ</i>的值. |
| | | </p> |
| | | <examinations :cardList="questionData[217]" sourceType="json" inputBc="#d3edfa" |
| | | v-if="questionData"></examinations> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | <!-- 211 --> |
| | | <div class="page-box" page="218"> |
| | | <div v-if="showPageList.indexOf(218) > -1"> |
| | | <ul class="page-header-box"> |
| | | <li> |
| | | <p>第五单元 三角函数</p> |
| | | </li> |
| | | <li> |
| | | <p><span>211</span></p> |
| | | </li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <div class="bj"> |
| | | <p>7.已知tan <i>α</i>=2,求下列各式的值.</p> |
| | | <p> |
| | | (1) |
| | | <math display="0"> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>+</mo> |
| | | <mn>3</mn> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>+</mo> |
| | | <mn>2</mn> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | </math>; |
| | | </p> |
| | | <p> |
| | | (2) |
| | | <math display="0"> |
| | | <mfrac> |
| | | <mrow> |
| | | <msup> |
| | | <mi>sin</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>+</mo> |
| | | <mn>3</mn> |
| | | <msup> |
| | | <mi>cos</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <msup> |
| | | <mi>sin</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | <msup> |
| | | <mi>cos</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p>8.求使下列函数取得最大值、最小值时<i>x</i>的集合.</p> |
| | | <p>(1) <i>y</i>=-1+2sin <i>x</i>;</p> |
| | | <p> |
| | | (2) |
| | | <math display="0"> |
| | | <mi>y</mi> |
| | | <mo>=</mo> |
| | | <mn>1</mn> |
| | | <mo>+</mo> |
| | | <msqrt> |
| | | <mn>2</mn> |
| | | </msqrt> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | <span class="bj-sp"><b>水平二</b></span> |
| | | </p> |
| | | <p> |
| | | 1.在半径为10 cm |
| | | 的圆中,60°的圆心角所对的弧长是____,对应的扇形面积是____. |
| | | </p> |
| | | <p>2.求下列指定范围内的角<i>x</i>的集合.</p> |
| | | <p> |
| | | (1) |
| | | <math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>,<i>x</i>∈-π,π,则<i>x</i>=____; |
| | | </p> |
| | | <p> |
| | | (2) |
| | | <math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>2</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>, <i>x</i>∈0,2π,则<i>x</i>=____; |
| | | </p> |
| | | <p> |
| | | (3) |
| | | <math display="0"> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mi>x</mi> |
| | | <mo>≠</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mi>k</mi> |
| | | <mi>π</mi> |
| | | <mo>,</mo> |
| | | <mi>k</mi> |
| | | <mo>∈</mo> |
| | | <mrow> |
| | | <mi mathvariant="bold">Z</mi> |
| | | </mrow> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>, <i>x</i>∈-π,π,则<i>x</i>=____. |
| | | </p> |
| | | <p> |
| | | 3.已知<i>m</i><0,角<i>α</i>的终边经过点<i>P</i>(-3<i>m</i>,4<i>m</i>),求sin |
| | | <i>α</i>+2cos <i>α</i>的值. |
| | | </p> |
| | | <p>4.已知tan(π-<i>α</i>)=3,求下列各式的值.</p> |
| | | <p>(1) 2sin <i>α</i>·cos <i>α</i>;</p> |
| | | <p> |
| | | (2) |
| | | <math display="0"> |
| | | <mfrac> |
| | | <mrow> |
| | | <msup> |
| | | <mi>sin</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>⋅</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>−</mo> |
| | | <msup> |
| | | <mi>cos</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <msup> |
| | | <mi>cos</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>−</mo> |
| | | <mn>3</mn> |
| | | <msup> |
| | | <mi>sin</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>+</mo> |
| | | <mn>1</mn> |
| | | </mrow> |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p>5.用“五点法”画出下列函数的图像,并写出它们的周期.</p> |
| | | <p>(1) <i>y</i>=-5+2sin <i>x</i>;</p> |
| | | <p>(2) <i>y</i>=5-cos <i>x</i>.</p> |
| | | </div> |
| | | </div> |
| | | <div class="page-box hidePage" page="218"></div> |
| | | <!-- 解题思路弹窗 --> |
| | | <el-dialog :visible.sync="thinkingDialog" width="40%" :append-to-body="true" :show-close="false" |
| | | @close="closeDialog" class="thinkDialog"> |
| | | <div slot="title" class="think-header" |
| | | style="padding: 0; text-align: center; color: #333;display:flex;justify-content: center;"> |
| | | <span style=""> 分析 </span> |
| | | <svg style="position: absolute; right:10px;cursor: pointer;" @click="thinkingDialog = false" t="1718596022986" |
| | | class="icon" viewBox="0 0 1024 1024" version="1.1" xmlns="http://www.w3.org/2000/svg" p-id="4252" width="20" |
| | | height="20" xmlns:xlink="http://www.w3.org/1999/xlink"> |
| | | <path |
| | | d="M176.661601 817.172881C168.472798 825.644055 168.701706 839.149636 177.172881 847.338438 185.644056 855.527241 199.149636 855.298332 207.338438 846.827157L826.005105 206.827157C834.193907 198.355983 833.964998 184.850403 825.493824 176.661601 817.02265 168.472798 803.517069 168.701706 795.328267 177.172881L176.661601 817.172881Z" |
| | | fill="#979797" p-id="4253"></path> |
| | | <path |
| | | d="M795.328267 846.827157C803.517069 855.298332 817.02265 855.527241 825.493824 847.338438 833.964998 839.149636 834.193907 825.644055 826.005105 817.172881L207.338438 177.172881C199.149636 168.701706 185.644056 168.472798 177.172881 176.661601 168.701706 184.850403 168.472798 198.355983 176.661601 206.827157L795.328267 846.827157Z" |
| | | fill="#979797" p-id="4254"></path> |
| | | </svg> |
| | | </div> |
| | | </div> |
| | | |
| | | |
| | | <ul> |
| | | <li v-for="(item, index) in thinkData" :key="index"> |
| | | <div v-if="index <= showIndex" style="display: flex"> |
| | | <span style="position: relative"> |
| | | <span style="position: absolute; top: 16px; left: 13px; color: #fff">{{ index + 1 }}</span> |
| | | <img src="../../assets/images/icon/blue-group.png" alt="" style="margin-right: 10px" |
| | | v-if="index < thinkOne.length - 1" /> |
| | | <img src="../../assets/images/icon/blue.png" alt="" v-if="index == thinkOne.length - 1" |
| | | style="margin-right: 10px" /> |
| | | </span> |
| | | <p class="txt-p" v-html="item"></p> |
| | | </div> |
| | | </li> |
| | | </ul> |
| | | <div @click="changeNext" style=" |
| | | display: flex; |
| | | flex-direction: column; |
| | | align-items: center; |
| | | justify-content: center; |
| | | "> |
| | | <img src="../../assets/images/icon/mouse.png" alt="" v-if="showIndex < thinkData.length - 1" /> |
| | | <svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" t="1710234570135" |
| | | class="icon" viewBox="0 0 1024 1024" version="1.1" p-id="5067" width="15" height="15"> |
| | | <path |
| | | d="M2.257993 493.371555 415.470783 906.584344 512 1003.113561 608.529217 906.584344 1021.742007 493.371555 925.212789 396.842337 512 810.055127 98.787211 396.842337Z" |
| | | fill="#1296db" p-id="5068" /> |
| | | <path |
| | | d="M2.257993 117.980154 415.470783 531.192944 512 627.722161 608.529217 531.192944 1021.742007 117.980154 925.212789 21.450937 512 434.663727 98.787211 21.450937Z" |
| | | fill="#1296db" p-id="5069" /> |
| | | </svg> |
| | | </div> |
| | | </el-dialog> |
| | | </div> |
| | | </template> |
| | | |
| | | <script> |
| | | import paint from '@/components/paint/index.vue' |
| | | import examinations from "@/components/examinations/index.vue"; |
| | | import fillInTable from "@/components/fillInTable/index.vue"; |
| | | const handleShow = (num) => { |
| | | const obj = {} |
| | | for (let index = 0; index < num; index++) { |
| | | obj['isShowAnswer' + index] = false |
| | | } |
| | | return obj |
| | | } |
| | | const showObj = handleShow(60) |
| | | export default { |
| | | name: '', |
| | | name: "", |
| | | props: { |
| | | showPageList: { |
| | | type: Array, |
| | | default: [], |
| | | }, |
| | | questionData: { |
| | | type: Object, |
| | | }, |
| | | }, |
| | | components: {}, |
| | | components: { examinations, fillInTable,paint }, |
| | | data() { |
| | | return {} |
| | | return { |
| | | ...showObj, |
| | | isShowAnswer:false, |
| | | queryDataOne: { |
| | | stemTxt:"完成下表,并利用“五点法”画出<i>y</i>=3sin <i>x</i>在区间[0,2π]内的简图,并说明<i>y</i>=3sin <i>x</i>的图像与正弦函数<i>y</i>=sin <i>x</i>的图像的区别和联系.", |
| | | showData: [ |
| | | ["<i>x</i>", "0", '<math display="block"><mfrac><mn>1</mn><mn>2</mn></mfrac></math>', "1", '<math display="block"><mfrac><mn>3</mn><mn>2</mn></mfrac></math>', "2"], |
| | | ["<i>y</i>=sin <i>x</i>", "0", "1", "0", "-1", "0"], |
| | | ["<i>y</i>=3sin <i>x</i>", "", "", "", "", ""], |
| | | ], |
| | | answer:"0,3,0,-3,0" |
| | | }, |
| | | queryDataTwo:{ |
| | | stemTxt:"完成下表,利用“五点法”画出y=1-cos x在区间[0,2π]内的简图,并说明y=1-cos x的图像与y=cos x的图像的区别和联系.", |
| | | showData: [ |
| | | ["x", "0", '<math display="block"><mfrac><mi>π</mi><mn>2</mn></mfrac></math>', "1", "3/2", "2"], |
| | | ["y=cosx", "", "", "", "", ""], |
| | | ["y=1-cosx", "", "", "", "", ""], |
| | | ], |
| | | answer:"<p>1,0,-1,0,1</p><p>0,1,2,1,0</p>" |
| | | }, |
| | | showIndex:0, |
| | | thinkingDialog: false, |
| | | thinkData:[], |
| | | thinkOne:[ |
| | | '因为sin <i>α</i>=-0.8572<0,在[0,2π]范围内有两个<i>α</i>值满足条件,它们分别位于第三象限和第四象限,即<i>α</i>在[π,2π]范围内.可用科学计算器先求出sin<i>α</i>=0.857 2所对应的锐角,再利用诱导公式求出所求的角.' |
| | | ] |
| | | } |
| | | }, |
| | | computed: {}, |
| | | watch: {}, |
| | | created() { }, |
| | | mounted() { }, |
| | | methods: {}, |
| | | methods:{ |
| | | hadleAnswer(index) { |
| | | this['isShowAnswer' + index] = !this['isShowAnswer' + index] |
| | | }, |
| | | openDialog(queryData) { |
| | | this.thinkData = queryData |
| | | this.thinkingDialog = !this.thinkingDialog |
| | | }, |
| | | closeDialog() { |
| | | this.showIndex = 0 |
| | | }, |
| | | changeNext() { |
| | | if (this.showIndex < this.thinkData.length - 1) this.showIndex = this.showIndex + 1 |
| | | } |
| | | } |
| | | } |
| | | </script> |
| | | |
| | | <style lang="less" scoped></style> |
| | | <style lang="less" scoped> |
| | | .table-answer-box { |
| | | padding: 4px; |
| | | border: 1px solid #00adee; |
| | | display: flex; |
| | | } |
| | | li { |
| | | list-style: none; |
| | | } |
| | | </style> |