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| | | <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" /> |
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| | | <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. |
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| | | <div v-if="showPageList.indexOf(161) > -1"> |
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| | | <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) |
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| | | </ul> |
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| | | <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="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> |
| | |
| | | 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]" :hideCollect="true" sourceType="json" inputBc="#d3edfa" |
| | | v-if="questionData"></examinations> |
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| | | <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> |
| | |
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| | | </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> |
| | |
| | | <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. |
| | | (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> |
| | | (3) 因为-890°=190°-3×360°,所以-890°角与190°角终边相同,是第三象限角. |
| | | (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. |
| | |
| | | </div> |
| | | </div> |
| | | </div> |
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| | | <div class="page-box" page="167"> |
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| | |
| | | ={<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> |
| | | <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]" :hideCollect="true" sourceType="json" inputBc="#d3edfa" |
| | | v-if="questionData"></examinations> |
| | | </div> |
| | | </div> |
| | | </div> |
| | |
| | | <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]" :hideCollect="true" 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. |
| | |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 164 --> |
| | | <div class="page-box" page="171"> |
| | | <div v-if="showPageList.indexOf(171) > -1"> |
| | |
| | | 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 class="center"><img class="img-c" alt="" src="../../assets/images/0175-3.jpg" /></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 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) |
| | |
| | | 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 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 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> |
| | | <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> |
| | | <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>____. |
| | | </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> |
| | | <examinations :cardList="questionData[171]" :hideCollect="true" 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 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"> |
| | |
| | | </math>,求该弧形高架桥的转弯半径(结果精确到1 m). |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 由题意可知,<i>l</i>=1 200,<math display="0"> |
| | | <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> |
| | |
| | | <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> |
| | | |
| | | <!-- 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 |
| | |
| | | </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> |
| | | <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"> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | </math>,半径为5 cm,则此扇形的弧长为____cm,面积为____cm<sup>2</sup>. |
| | | </p> |
| | | <examinations :cardList="questionData[173]" :hideCollect="true" 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]" :hideCollect="true" 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 |
| | |
| | | <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> |
| | | <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, |
| | | <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"> |
| | |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | <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.(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> |
| | | <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>= |
| | | ____. |
| | | </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> |
| | | <examinations :cardList="questionData[176]" :hideCollect="true" sourceType="json" inputBc="#d3edfa" |
| | | 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> |
| | | 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> |
| | |
| | | </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. |
| | |
| | | <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]" :hideCollect="true" 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> |
| | |
| | | <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° |
| | | <span class="zt-ls"><b>解</b></span> 5sin 180°-4sin 90°+2 tan |
| | | 180°-7sin 270° |
| | | </p> |
| | | <p>=5×0-4×1+2×0-7×(-1)</p> |
| | | <p>=3.</p> |
| | |
| | | </mtable> |
| | | </math> |
| | | </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.<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>( ). |
| | | </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> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mn>2</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>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>____. |
| | | </p> |
| | | <examinations :cardList="questionData[180] ? questionData[180][1] : []" :hideCollect="true" |
| | | 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] : []" :hideCollect="true" |
| | | 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"> |
| | |
| | | </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. |
| | |
| | | <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] : []" :hideCollect="true" |
| | | 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] : []" :hideCollect="true" |
| | | sourceType="json" inputBc="#d3edfa" v-if="questionData"></examinations> |
| | | </div> |
| | | </div> |
| | | </div> |
| | |
| | | <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> |
| | |
| | | </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> |
| | | <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> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>25</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> |
| | | <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>4</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> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | D.<math display="0"> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | </math> |
| | | </p> |
| | | <examinations :cardList="questionData[186]" :hideCollect="true" 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5-20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> |
| | |
| | | </mtable> |
| | | </math> |
| | | </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 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> |
| | | </math> |
| | | </p> |
| | | <examinations :cardList="questionData[188]" :hideCollect="true" 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5-22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> |
| | |
| | | </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]" :hideCollect="true" 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> |
| | | 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> |
| | | 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]" :hideCollect="true" 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> |
| | |
| | | <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 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 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 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 class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0197-4.jpg" /> |
| | | </p> |
| | | <p> |
| | | 所以 |
| | | <math display="0"> |
| | |
| | | (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 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 class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0197-7.jpg" /> |
| | | </p> |
| | | <p> |
| | | 所以<math display="0"> |
| | | <mi>tan</mi> |
| | |
| | | <mo>.</mo> |
| | | </math> |
| | | </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.利用科学计算器求值.(结果精确到0.01)</p> |
| | | <p> |
| | | (1) sin 1 480°10′12″____;(2) |
| | | <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> |
| | | <mo>≈</mo> |
| | | </math>____; |
| | | </p> |
| | | <p>(3) tan(-3.6)≈____.</p> |
| | | <examinations :cardList="questionData[193]" :hideCollect="true" sourceType="json" inputBc="#d3edfa" |
| | | v-if="questionData"></examinations> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </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]" :hideCollect="true" 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> |
| | |
| | | <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 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="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 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="center"> |
| | | <img class="img-d" alt="" src="../../assets/images/0201-5.jpg" /> |
| | | </p> |
| | | <p class="img">图5-28</p> |
| | | </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]" :hideCollect="true" 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> |
| | |
| | | </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> |
| | | <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> |
| | | <mrow> |
| | | <mi>a</mi> |
| | | <mo>−</mo> |
| | | <mn>1</mn> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </math>,则<i>a</i>的取值范围为____. |
| | | </p> |
| | | <p> |
| | | 2.(1)函数<i>y</i>=1+0.6sin <i>x</i>的最大值为____, 最小值为____; |
| | | </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> |
| | | (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____. |
| | | </p> |
| | | <examinations :cardList="questionData[199]" :hideCollect="true" 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> |
| | | <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> |
| | |
| | | </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"> |
| | |
| | | <li>上册</li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | |
| | | <p> |
| | | (2) 因为 <math display="0"> |
| | | <mo>−</mo> |
| | |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math> |
| | | <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>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°. |
| | | </p> |
| | | <examinations :cardList="questionData[201] ? questionData[201][1] : []" :hideCollect="true" |
| | | sourceType="json" inputBc="#d3edfa" v-if="questionData"></examinations> |
| | | </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"> |
| | | <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> |
| | | </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> |
| | | <mrow> |
| | | <mn>6</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>7</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>. |
| | | </p> |
| | | <examinations :cardList="questionData[201] ? questionData[201][2] : []" :hideCollect="true" |
| | | 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> |
| | |
| | | <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="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> |
| | | </div> |
| | | |
| | | <!-- 197 --> |
| | | <div class="page-box" page="204"> |
| | | <div v-if="showPageList.indexOf(204) > -1"> |
| | |
| | | <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="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0208-1.jpg" /> |
| | | </p> |
| | | <p class="center"><img class="img-c" alt="" src="../../assets/images/0208-2.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> |
| | | <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5-12),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 |
| | |
| | | <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] : []" :hideCollect="true" |
| | | 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. |
| | |
| | | </mrow> |
| | | <mo>.</mo> |
| | | </math> |
| | | <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.(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] : []" :hideCollect="true" |
| | | 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]" :hideCollect="true" 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"> |
| | |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 202 --> |
| | | <div class="page-box" page="209"> |
| | | <div v-if="showPageList.indexOf(209) > -1"> |
| | |
| | | </mfrac> |
| | | </math>. |
| | | </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.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> |
| | | |
| | | <examinations :cardList="questionData[209]" :hideCollect="true" sourceType="json" inputBc="#d3edfa" |
| | | v-if="questionData"></examinations> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 203 --> |
| | | <div class="page-box" page="210"> |
| | | <div v-if="showPageList.indexOf(210) > -1"> |
| | |
| | | </li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <div class="bj"> |
| | | <p> |
| | | 3.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> |
| | | <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>,且<i>x</i>∈[0,2π],则<i>x</i>的值为____. |
| | | </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 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> |
| | | <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> |
| | |
| | | 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 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 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 |
| | |
| | | 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 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 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; |
| | |
| | | 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 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 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 |
| | |
| | | <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 |
| | | <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 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 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"> |
| | |
| | | <p>第五单元 三角函数</p> |
| | | </li> |
| | | <li> |
| | | <p><span>205</span></p> |
| | | <p><span>205-206</span></p> |
| | | </li> |
| | | </ul> |
| | | |
| | | <div class="padding-116"> |
| | | <p>即</p> |
| | | <p class="center">sin 1.029 8≈0.857 2.</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> |
| | | <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>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> |
| | | <examinations :cardList="questionData[212] ? questionData[212][1] : []" :hideCollect="true" |
| | | sourceType="json" inputBc="#d3edfa" v-if="questionData"></examinations> |
| | | </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> |
| | | <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>,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> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>2</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>,0°≤<i>x</i>≤180°,则<i>x</i>的值为____. |
| | | </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____. |
| | | </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) |
| | | </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> |
| | | (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. |
| | | </p> |
| | | <examinations :cardList="questionData[212] ? questionData[212][2] : []" :hideCollect="true" |
| | | 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]" :hideCollect="true" 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> |
| | | </div> |
| | | |
| | | |
| | | <div class="page-box hidePage" page="218"></div> |
| | | </div> |
| | | </template> |
| | | |
| | | <script> |
| | | import paint from '@/components/paint/index.vue' |
| | | import examinations from "@/components/examinations/index.vue"; |
| | | import fillInTable from "@/components/fillInTable/index.vue"; |
| | | export default { |
| | | name: '', |
| | | name: "", |
| | | props: { |
| | | showPageList: { |
| | | type: Array, |
| | | default: [], |
| | | }, |
| | | questionData: { |
| | | type: Object, |
| | | }, |
| | | }, |
| | | components: {}, |
| | | components: { examinations, fillInTable,paint }, |
| | | data() { |
| | | return {} |
| | | return { |
| | | 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>" |
| | | } |
| | | |
| | | } |
| | | }, |
| | | computed: {}, |
| | | watch: {}, |
| | | created() { }, |
| | | mounted() { }, |
| | | methods: {}, |
| | | } |
| | | </script> |
| | | |
| | | <style lang="less" scoped></style> |
| | | <style lang="less" scoped> |
| | | .table-answer-box { |
| | | padding: 4px; |
| | | border: 1px solid #00adee; |
| | | display: flex; |
| | | } |
| | | </style> |