| | |
| | | <template> |
| | | <div class="chapter" num="5"> |
| | | <div class="chapter" num="6"> |
| | | <!-- 第五单元首页 --> |
| | | <div class="page-box" page="160"> |
| | | <div v-if="showPageList.indexOf(160) > -1"> |
| | |
| | | <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 class="p-btn" > |
| | | <span>(1) 225°;</span> |
| | | <span class="btn-box" @click="hadleAnswer(0)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p class="img">图5-4</p> |
| | | <p>(1) 225°;(2) -300°.</p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) |
| | | 以<i>x</i>轴的非负半轴为始边,逆时针方向旋转225°,即形成225°角,如图5-4(1) |
| | | 所示.因为225°角的终边在第三象限内,所以225°角是第三象限角. |
| | | <div v-if="isShowAnswer0" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) |
| | | 以<i>x</i>轴的非负半轴为始边,逆时针方向旋转225°,即形成225°角,如图5-4(1) |
| | | 所示.因为225°角的终边在第三象限内,所以225°角是第三象限角. |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0168-1.jpg" /> |
| | | </p> |
| | | <p class="img">图5-4</p> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span>(2) -300°.</span> |
| | | <span class="btn-box" @click="hadleAnswer(1)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p> |
| | | (2) |
| | | <p v-if="isShowAnswer1" > |
| | | <span class="zt-ls"><b>解</b></span>(2) |
| | | 以<i>x</i>轴的非负半轴为始边,顺时针方向旋转300°,即形成-300°角,如图5-4(2) |
| | | 所示.因为-300°角的终边在第一象限内,所以-300°角是第一象限角. |
| | | </p> |
| | |
| | | <p>第五单元 三角函数</p> |
| | | </li> |
| | | <li> |
| | | <p><span>159</span></p> |
| | | <p><span>159-160</span></p> |
| | | </li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | |
| | | <p> |
| | | <span class="zt-ls"><b>例1</b></span> 在0°~360°内,找出与下列各角终边相同的角,并分别判断它们是第几象限角. |
| | | </p> |
| | | <p>(1) 600°;(2) -230°;(3) -890°.</p> |
| | | <p> |
| | | <p class="p-btn" > |
| | | <span>(1) 600°;</span> |
| | | <span class="btn-box" @click="hadleAnswer(2)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p v-if="isShowAnswer2" > |
| | | <span class="zt-ls"><b>解</b></span>(1) 因为600°=240°+360°,所以600°角与240°角终边相同,是第三象限角. |
| | | </p> |
| | | <p> |
| | | (2) |
| | | <p class="p-btn" > |
| | | <span>(2) -230°;</span> |
| | | <span class="btn-box" @click="hadleAnswer(3)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p v-if="isShowAnswer3" > |
| | | <span class="zt-ls"><b>解</b></span>(2) |
| | | 因为-230°=130°-360°,所以-230°角与130°角终边相同,是第二象限角. |
| | | </p> |
| | | <p> |
| | | (3) |
| | | <p class="p-btn" > |
| | | <span>(3) -890°.</span> |
| | | <span class="btn-box" @click="hadleAnswer(4)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p v-if="isShowAnswer4" > |
| | | <span class="zt-ls"><b>解</b></span>(3) |
| | | 因为-890°=190°-3×360°,所以-890°角与190°角终边相同,是第三象限角. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>例2</b></span> 写出下列角的集合. |
| | | </p> |
| | | <p>(1) 终边在<i>y</i>轴正半轴上的角的集合;</p> |
| | | <p>(2) 终边在<i>y</i>轴负半轴上的角的集合;</p> |
| | | <p>(3) 终边在<i>y</i>轴上的角的集合.</p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) 在0°~360°内,终边在<i>y</i>轴正半轴上的角是90°角, |
| | | <p class="p-btn" > |
| | | <span>(1) 终边在<i>y</i>轴正半轴上的角的集合;</span> |
| | | <span class="btn-box" @click="hadleAnswer(5)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p>所以,终边在<i>y</i>轴正半轴上的角的集合是</p> |
| | | <p class="center"> |
| | | <i>S</i>1={<i>β</i>|<i>β</i>=90°+<i>k</i>·360°,<i>k</i>∈<b>Z</b>}. |
| | | <div v-if="isShowAnswer5" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) 在0°~360°内,终边在<i>y</i>轴正半轴上的角是90°角, |
| | | </p> |
| | | <p>所以,终边在<i>y</i>轴正半轴上的角的集合是</p> |
| | | <p class="center"> |
| | | <i>S</i>1={<i>β</i>|<i>β</i>=90°+<i>k</i>·360°,<i>k</i>∈<b>Z</b>}. |
| | | </p> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span>(2) 终边在<i>y</i>轴负半轴上的角的集合;</span> |
| | | <span class="btn-box" @click="hadleAnswer(6)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p>(2) 在0°~360°内,终边在<i>y</i>轴负半轴上的角是270°角,</p> |
| | | <p>所以,终边在<i>y</i>轴负半轴上的角的集合是</p> |
| | | <p class="center"> |
| | | <i>S</i>2={<i>β</i>|<i>β</i>=270°+<i>k</i>·360°,<i>k</i>∈<b>Z</b>}. |
| | | <div v-if="isShowAnswer6" > |
| | | <p><span class="zt-ls"><b>解</b></span>(2) 在0°~360°内,终边在<i>y</i>轴负半轴上的角是270°角,</p> |
| | | <p>所以,终边在<i>y</i>轴负半轴上的角的集合是</p> |
| | | <p class="center"> |
| | | <i>S</i>2={<i>β</i>|<i>β</i>=270°+<i>k</i>·360°,<i>k</i>∈<b>Z</b>}. |
| | | </p> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span>(3) 终边在<i>y</i>轴上的角的集合.</span> |
| | | <span class="btn-box" @click="hadleAnswer(7)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | <!-- 160 --> |
| | | <div class="page-box" page="167"> |
| | | <div v-if="showPageList.indexOf(167) > -1"> |
| | | <ul class="page-header-odd fl al-end"> |
| | | <li>160</li> |
| | | <li>数学.基础模块</li> |
| | | <li>上册</li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <p>(3) 终边在<i>y</i>轴上的角的集合是</p> |
| | | <p><i>S</i>=<i>S</i><sub>1</sub>∪<i>S</i><sub>2</sub></p> |
| | | <p> |
| | | ={<i>β</i>|<i>β</i>=90°+<i>k</i>·360°,<i>k</i>∈<b>Z</b>}∪{<i>β</i>|<i>β</i>=270°+<i>k</i>·360°,<i>k</i>∈<b>Z</b>} |
| | | </p> |
| | | <p> |
| | | ={<i>β</i>|<i>β</i>=90°+2<i>k</i>·180°,<i>k</i>∈<b>Z</b>}∪{<i>β</i>|<i>β</i>=90°+(2<i>k</i>+1)·180°,<i>k</i>∈<b>Z</b>} |
| | | </p> |
| | | <p>={<i>β</i>|<i>β</i>=90°+<i>m</i>·180°,<i>m</i>∈<b>Z</b>}.</p> |
| | | <div v-if="isShowAnswer7" > |
| | | <p> <span class="zt-ls"><b>解</b></span>(3) 终边在<i>y</i>轴上的角的集合是</p> |
| | | <p><i>S</i>=<i>S</i><sub>1</sub>∪<i>S</i><sub>2</sub></p> |
| | | <p> |
| | | ={<i>β</i>|<i>β</i>=90°+<i>k</i>·360°,<i>k</i>∈<b>Z</b>}∪{<i>β</i>|<i>β</i>=270°+<i>k</i>·360°,<i>k</i>∈<b>Z</b>} |
| | | </p> |
| | | <p> |
| | | ={<i>β</i>|<i>β</i>=90°+2<i>k</i>·180°,<i>k</i>∈<b>Z</b>}∪{<i>β</i>|<i>β</i>=90°+(2<i>k</i>+1)·180°,<i>k</i>∈<b>Z</b>} |
| | | </p> |
| | | <p>={<i>β</i>|<i>β</i>=90°+<i>m</i>·180°,<i>m</i>∈<b>Z</b>}.</p> |
| | | </div> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | <!-- 160 --> |
| | | <div class="page-box hidePage" page="167"> |
| | | </div> |
| | | <!-- 161 --> |
| | | <div class="page-box" page="168"> |
| | |
| | | <p><span>161</span></p> |
| | | </li> |
| | | </ul> |
| | | |
| | | <div class="padding-116"> |
| | | <h3 id="c050">习题5.1<span class="fontsz2">>>></span></h3> |
| | | <div class="bj"> |
| | |
| | | <img class="img-c" alt="" src="../../assets/images/0174-6.jpg" /> |
| | | </p> |
| | | <p class="img">图5-8</p> |
| | | <p> |
| | | <span class="zt-ls"><b>例1</b></span> 把下列各角化为弧度. |
| | | <p class="p-btn" > |
| | | <span><span class="zt-ls"><b>例1</b></span> 把下列各角化为弧度.</span> |
| | | <span class="btn-box" @click="hadleAnswer(8)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p>(1) 30°;(2) -225°;(3) 0°.</p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(1)</mo> |
| | | <msup> |
| | | <div v-if="isShowAnswer8" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(1)</mo> |
| | | <msup> |
| | | <mn>30</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mn>30</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mn>30</mn> |
| | | <mo>×</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>180</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(2)</mo> |
| | | <mo>−</mo> |
| | | <msup> |
| | | <mn>225</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mn>225</mn> |
| | | <mo>×</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>180</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mo>×</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(3)</mo> |
| | | <msup> |
| | | <mn>180</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(2)</mo> |
| | | <mo>−</mo> |
| | | <msup> |
| | | <mn>225</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mn>225</mn> |
| | | <mo>×</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>180</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(3)</mo> |
| | | <msup> |
| | | <mn>0</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mn>0</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mn>0</mn> |
| | | <mo>×</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>180</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mn>0</mn> |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>例2</b></span> 把下列各角化为角度. |
| | | <mo>×</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>180</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mn>0</mn> |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span><span class="zt-ls"><b>例2</b></span> 把下列各角化为角度.</span> |
| | | <span class="btn-box" @click="hadleAnswer(9)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p> |
| | | (1) |
| | |
| | | </mfrac> |
| | | </math>;(2) 5rad(结果精确到0.01). |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(1)</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <div v-if="isShowAnswer9" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(1)</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <msup> |
| | | <mn>180</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <msup> |
| | | <mn>180</mn> |
| | | <mn>60</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <msup> |
| | | <mn>60</mn> |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(2)</mo> |
| | | <mn>5</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | <mi mathvariant="normal">r</mi> |
| | | <mi mathvariant="normal">a</mi> |
| | | <mi mathvariant="normal">d</mi> |
| | | </mrow> |
| | | </msup> |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(2)</mo> |
| | | <mn>5</mn> |
| | | <mrow> |
| | | <mi mathvariant="normal">r</mi> |
| | | <mi mathvariant="normal">a</mi> |
| | | <mi mathvariant="normal">d</mi> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mn>5</mn> |
| | | <mo>×</mo> |
| | | <mfrac> |
| | | <mo>=</mo> |
| | | <mn>5</mn> |
| | | <mo>×</mo> |
| | | <mfrac> |
| | | <msup> |
| | | <mn>180</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mi>π</mi> |
| | | </mfrac> |
| | | <mo>≈</mo> |
| | | <msup> |
| | | <mn>180</mn> |
| | | <mn>286.44</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mi>π</mi> |
| | | </mfrac> |
| | | <mo>≈</mo> |
| | | <msup> |
| | | <mn>286.44</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | <div class="bk"> |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | </div> |
| | | <div class="bk mt-60"> |
| | | <div class="bj1"> |
| | | <p class="left"> |
| | | <img class="img-gn1" alt="" src="../../assets/images/tbts.jpg" /> |
| | |
| | | <p> |
| | | <span class="zt-ls"><b>例3</b></span> 利用科学计算器,把下列各角进行弧度与角度的互化.(结果精确到0.01) |
| | | </p> |
| | | <p>(1) -5.6;(2) 154°13′.</p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) |
| | | 先将科学计算器的精确度设置为0.01,再将科学计算器设置为角度计算模式,科学计算器Ⅰ按<img class="inline" alt="" |
| | | src="../../assets/images/0175-1.jpg" />,科学计算器Ⅱ按<img class="inline" alt="" |
| | | src="../../assets/images/0175-2.jpg" />.之后依次按下列各键. |
| | | <p class="p-btn" > |
| | | <span>(1) -5.6;</span> |
| | | <span class="btn-box" @click="hadleAnswer(10)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0175-3.jpg" /> |
| | | <div v-if="isShowAnswer10" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) |
| | | 先将科学计算器的精确度设置为0.01,再将科学计算器设置为角度计算模式,科学计算器Ⅰ按<img class="inline" alt="" |
| | | src="../../assets/images/0175-1.jpg" />,科学计算器Ⅱ按<img class="inline" alt="" |
| | | src="../../assets/images/0175-2.jpg" />.之后依次按下列各键. |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0175-3.jpg" /> |
| | | </p> |
| | | <p>结果显示:</p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0175-4.jpg" /> |
| | | </p> |
| | | <p>所以 -5.6 <i>rad</i> ≈-320.86°.</p> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span>(2) 154°13′.</span> |
| | | <span class="btn-box" @click="hadleAnswer(11)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p>结果显示:</p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0175-4.jpg" /> |
| | | </p> |
| | | <p>所以 -5.6 <i>rad</i> ≈-320.86°.</p> |
| | | <p> |
| | | (2) |
| | | 先将科学计算器的精确度设置为0.01,再将科学计算器设置为弧度计算模式,科学计算器Ⅰ按<img class="inline" alt="" |
| | | src="../../assets/images/0175-5.jpg" />,科学计算器Ⅱ按<img class="inline" alt="" |
| | | src="../../assets/images/0175-6.jpg" />.之后依次按下列各键. |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0175-7.jpg" /> |
| | | </p> |
| | | <p>结果显示:</p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0175-8.jpg" /> |
| | | </p> |
| | | <p>所以 154°13′≈2.69 rad.</p> |
| | | <div v-if="isShowAnswer11" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(2) |
| | | 先将科学计算器的精确度设置为0.01,再将科学计算器设置为弧度计算模式,科学计算器Ⅰ按<img class="inline" alt="" |
| | | src="../../assets/images/0175-5.jpg" />,科学计算器Ⅱ按<img class="inline" alt="" |
| | | src="../../assets/images/0175-6.jpg" />.之后依次按下列各键. |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0175-7.jpg" /> |
| | | </p> |
| | | <p>结果显示:</p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0175-8.jpg" /> |
| | | </p> |
| | | <p>所以 154°13′≈2.69 rad.</p> |
| | | </div> |
| | | <calculator /> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.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"> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </math>,求该弧形高架桥的转弯半径(结果精确到1 m). |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例1</b></span> 截至2021年4月,中国高速公路总里程约为16万千米,位居全球第一.某高速公路转弯处为一弧形高架桥,测得此处公路中线的总长为1 |
| | | 200 m,该弧形高架桥所对应的圆心角为<math display="0"> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </math>,求该弧形高架桥的转弯半径(结果精确到1 m). |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(12)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 由题意可知,<i>l</i>=1 |
| | | 200,<math display="0"> |
| | | <mi>α</mi> |
| | | <div v-if="isShowAnswer12" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 由题意可知,<i>l</i>=1 |
| | | 200,<math display="0"> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </math>,由<i>l</i>=<i>αr</i>可得 |
| | | </p> |
| | | <math display="block"> |
| | | <mi>r</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>l</mi> |
| | | <mi>α</mi> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1200</mn> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | <mn>1200</mn> |
| | | <mo>×</mo> |
| | | <mn>5</mn> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </math>,由<i>l</i>=<i>αr</i>可得 |
| | | </p> |
| | | <math display="block"> |
| | | <mi>r</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>l</mi> |
| | | <mi>α</mi> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1200</mn> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>1200</mn> |
| | | <mo>×</mo> |
| | | <mn>5</mn> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>2000</mn> |
| | | <mi>π</mi> |
| | | </mfrac> |
| | | <mo>≈</mo> |
| | | <mn>645</mn> |
| | | <mo stretchy="false">(</mo> |
| | | <mrow> |
| | | <mtext> </mtext> |
| | | <mi mathvariant="normal">m</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>2000</mn> |
| | | <mi>π</mi> |
| | | </mfrac> |
| | | <mo>≈</mo> |
| | | <mn>645</mn> |
| | | <mo stretchy="false">(</mo> |
| | | <mrow> |
| | | <mtext> </mtext> |
| | | <mi mathvariant="normal">m</mi> |
| | | </mrow> |
| | | <mo stretchy="false">)</mo> |
| | | <mo>.</mo> |
| | | </math> |
| | | <p>所以,该弧形高架桥的转弯半径约为645 m.</p> |
| | | <mo stretchy="false">)</mo> |
| | | <mo>.</mo> |
| | | </math> |
| | | <p>所以,该弧形高架桥的转弯半径约为645 m.</p> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | |
| | | <img class="img-c" alt="" src="../../assets/images/0177-1.jpg" /> |
| | | </p> |
| | | <p class="img">图5-10</p> |
| | | <p> |
| | | <span class="zt-ls"><b>例2</b></span> 如图5-10所示,要在一块废铁皮上剪出一个扇形,用于制作一个圆锥筒,要求这个扇形的圆心角为60°,半径为90 |
| | | cm .请求出这个扇形的弧长与面积.(结果分别精确到0.01 cm和0.01 |
| | | cm<sup>2</sup>) |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例2</b></span> 如图5-10所示,要在一块废铁皮上剪出一个扇形,用于制作一个圆锥筒,要求这个扇形的圆心角为60°,半径为90 |
| | | cm .请求出这个扇形的弧长与面积.(结果分别精确到0.01 cm和0.01 |
| | | cm<sup>2</sup>) |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(13)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 由于<math display="0"> |
| | | <msup> |
| | | <mn>60</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math>, 所以 |
| | | </p> |
| | | <math display="block"> |
| | | <mtable columnalign="left" columnspacing="1em" rowspacing="4pt"> |
| | | <mtr> |
| | | <mtd> |
| | | <mi>l</mi> |
| | | <mo>=</mo> |
| | | <mi>α</mi> |
| | | <mi>r</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>×</mo> |
| | | <mn>90</mn> |
| | | <mo>=</mo> |
| | | <mn>30</mn> |
| | | <mi>π</mi> |
| | | <mo>≈</mo> |
| | | <mn>94.26</mn> |
| | | <mo stretchy="false">(</mo> |
| | | <div v-if="isShowAnswer13" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 由于<math display="0"> |
| | | <msup> |
| | | <mn>60</mn> |
| | | <mrow> |
| | | <mtext> </mtext> |
| | | <mi mathvariant="normal">c</mi> |
| | | <mi mathvariant="normal">m</mi> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | <mo stretchy="false">)</mo> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd> |
| | | <mi>S</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mi>r</mi> |
| | | <mi>l</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>×</mo> |
| | | <mn>90</mn> |
| | | <mo>×</mo> |
| | | <mn>30</mn> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mo>≈</mo> |
| | | <mn>4241.70</mn> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <msup> |
| | | <mrow> |
| | | <mtext> </mtext> |
| | | <mi mathvariant="normal">c</mi> |
| | | <mi mathvariant="normal">m</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>.</mo> |
| | | </mtd> |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | <p> |
| | | 所以,这个扇形的弧长约为94.26 cm,面积约为4 241.70 cm<sup>2</sup>. |
| | | </p> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math>, 所以 |
| | | </p> |
| | | <math display="block"> |
| | | <mtable columnalign="left" columnspacing="1em" rowspacing="4pt"> |
| | | <mtr> |
| | | <mtd> |
| | | <mi>l</mi> |
| | | <mo>=</mo> |
| | | <mi>α</mi> |
| | | <mi>r</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>×</mo> |
| | | <mn>90</mn> |
| | | <mo>=</mo> |
| | | <mn>30</mn> |
| | | <mi>π</mi> |
| | | <mo>≈</mo> |
| | | <mn>94.26</mn> |
| | | <mo stretchy="false">(</mo> |
| | | <mrow> |
| | | <mtext> </mtext> |
| | | <mi mathvariant="normal">c</mi> |
| | | <mi mathvariant="normal">m</mi> |
| | | </mrow> |
| | | <mo stretchy="false">)</mo> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd> |
| | | <mi>S</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mi>r</mi> |
| | | <mi>l</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>×</mo> |
| | | <mn>90</mn> |
| | | <mo>×</mo> |
| | | <mn>30</mn> |
| | | <mi>π</mi> |
| | | <mo>≈</mo> |
| | | <mn>4241.70</mn> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <msup> |
| | | <mrow> |
| | | <mtext> </mtext> |
| | | <mi mathvariant="normal">c</mi> |
| | | <mi mathvariant="normal">m</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>.</mo> |
| | | </mtd> |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | <p> |
| | | 所以,这个扇形的弧长约为94.26 cm,面积约为4 241.70 cm<sup>2</sup>. |
| | | </p> |
| | | </div> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 169 --> |
| | | <div class="page-box" page="176"> |
| | | <div v-if="showPageList.indexOf(176) > -1"> |
| | |
| | | </li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <p> |
| | | <span class="zt-ls"><b>例1</b></span> 如图5-14所示,已知<i>α</i>的终边经过点 <i>P</i>(3,-4), |
| | | 求sin<i>α</i>,cos<i>α</i>,tan<i>α</i>的值. |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例1</b></span> 如图5-14所示,已知<i>α</i>的终边经过点 <i>P</i>(3,-4), |
| | | 求sin<i>α</i>,cos<i>α</i>,tan<i>α</i>的值. |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(14)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0180-3.jpg" /> |
| | | </p> |
| | | <p class="img">图5-14</p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | 由已知有<i>x</i>=3,<i>y</i>=-4, |
| | | </p> |
| | | <p>则</p> |
| | | <math display="block"> |
| | | <mi>r</mi> |
| | | <mo>=</mo> |
| | | <msqrt> |
| | | <msup> |
| | | <mn>3</mn> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo>+</mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mn>4</mn> |
| | | <msup> |
| | | <mo stretchy="false">)</mo> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | </msqrt> |
| | | <mo>=</mo> |
| | | <mn>5</mn> |
| | | <mo>.</mo> |
| | | </math> |
| | | <p>于是</p> |
| | | <math display="block"> |
| | | <mtable columnalign="left" columnspacing="1em" rowspacing="4pt"> |
| | | <mtr> |
| | | <mtd> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>y</mi> |
| | | <mi>r</mi> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>4</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo>,</mo> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>x</mi> |
| | | <mi>r</mi> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo>,</mo> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>y</mi> |
| | | <mi>x</mi> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>4</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </mtd> |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | <div v-if="isShowAnswer36" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | 由已知有<i>x</i>=3,<i>y</i>=-4, |
| | | </p> |
| | | <p>则</p> |
| | | <math display="block"> |
| | | <mi>r</mi> |
| | | <mo>=</mo> |
| | | <msqrt> |
| | | <msup> |
| | | <mn>3</mn> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo>+</mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mn>4</mn> |
| | | <msup> |
| | | <mo stretchy="false">)</mo> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | </msqrt> |
| | | <mo>=</mo> |
| | | <mn>5</mn> |
| | | <mo>.</mo> |
| | | </math> |
| | | <p>于是</p> |
| | | <math display="block"> |
| | | <mtable columnalign="left" columnspacing="1em" rowspacing="4pt"> |
| | | <mtr> |
| | | <mtd> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>y</mi> |
| | | <mi>r</mi> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>4</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo>,</mo> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>x</mi> |
| | | <mi>r</mi> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo>,</mo> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>y</mi> |
| | | <mi>x</mi> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>4</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </mtd> |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | </div> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 170 --> |
| | | <div class="page-box" page="177"> |
| | | <div v-if="showPageList.indexOf(177) > -1"> |
| | |
| | | <p> |
| | | <span class="zt-ls"><b>例2</b></span> 确定下列各三角函数值的符号. |
| | | </p> |
| | | <p> |
| | | (1) sin(-210°);(2) tan760°;(3) |
| | | <math display="0"> |
| | | <p class="p-btn" > |
| | | <span>(1) sin(-210°);</span> |
| | | <span class="btn-box" @click="hadleAnswer(15)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <div v-if="isShowAnswer15" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) 因为-210°是第二象限角,所以 |
| | | </p> |
| | | <p class="center">sin(-210°)>0.</p> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span>(2) tan760°;</span> |
| | | <span class="btn-box" @click="hadleAnswer(16)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <div v-if="isShowAnswer16" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(2) |
| | | 因为760°=40°+2×360°,可知760°角与40°角的终边相同,是第一象限角,所以 |
| | | </p> |
| | | <p class="center">tan 760°>0.</p> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span> |
| | | (3) |
| | | <math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>17</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>12</mn> |
| | | </mfrac> |
| | | </math>. |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(17)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <div v-if="isShowAnswer17" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(3) 由<math display="0"> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>17</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>12</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mfrac> |
| | | <mn>5</mn> |
| | | <mn>12</mn> |
| | | </mfrac> |
| | | <mi>π</mi> |
| | | </math>,可看出<math display="0"> |
| | | <mi>π</mi> |
| | | <mo><</mo> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>12</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>6</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>12</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>,是第三象限角, |
| | | </p> |
| | | <p>所以</p> |
| | | <math display="block"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | |
| | | </mrow> |
| | | <mn>12</mn> |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) 因为-210°是第二象限角,所以 |
| | | </p> |
| | | <p class="center">sin(-210°)>0.</p> |
| | | <p> |
| | | (2) |
| | | 因为760°=40°+2×360°,可知760°角与40°角的终边相同,是第一象限角,所以 |
| | | </p> |
| | | <p class="center">tan 760°>0.</p> |
| | | <p> |
| | | (3) 由<math display="0"> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>17</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>12</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mfrac> |
| | | <mn>5</mn> |
| | | <mn>12</mn> |
| | | </mfrac> |
| | | <mi>π</mi> |
| | | </math>,可看出<math display="0"> |
| | | <mi>π</mi> |
| | | <mo><</mo> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>12</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>6</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>12</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>,是第三象限角, |
| | | <mn>0</mn> |
| | | </math> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例3</b></span> 根据sin <i>α</i>>0,且cos <i>α</i><0,确定<i>α</i>是第几象限角. |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(18)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p>所以</p> |
| | | <math display="block"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>17</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>12</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mn>0</mn> |
| | | </math> |
| | | <p> |
| | | <span class="zt-ls"><b>例3</b></span> 根据sin <i>α</i>>0,且cos <i>α</i><0,确定<i>α</i>是第几象限角. |
| | | </p> |
| | | <p> |
| | | <p v-if="isShowAnswer18"> |
| | | <span class="zt-ls"><b>解</b></span> 因为sin |
| | | <i>α</i>>0,所以<i>α</i>的终边在第一或第二象限或<i>y</i>轴的正半轴上;又因为cos<i>α</i><0,所以<i>α</i>的终边在第二或第三象限或<i>x</i>轴的负半轴上.因此,<i>α</i>为第二象限角. |
| | | </p> |
| | |
| | | <p>第五单元 三角函数</p> |
| | | </li> |
| | | <li> |
| | | <p><span>173</span></p> |
| | | <p><span>173-174</span></p> |
| | | </li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <p> |
| | | <span class="zt-ls"><b>例4</b></span> 求5sin180°-4sin90°+2tan180°-7sin270°的值. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 5sin 180°-4sin 90°+2 tan |
| | | 180°-7sin 270° |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例4</b></span> 求5sin180°-4sin90°+2tan180°-7sin270°的值. |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(19)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p>=5×0-4×1+2×0-7×(-1)</p> |
| | | <p>=3.</p> |
| | | <p> |
| | | <span class="zt-ls"><b>例5</b></span> 求<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | <mo>−</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>π</mi> |
| | | <mo>−</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <div v-if="isShowAnswer19" > |
| | | <p> |
| | | <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> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例5</b></span> 求<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>的值. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mtable displaystyle="true" |
| | | columnalign="right left right left right left right left right left right left" |
| | | columnspacing="0em 2em 0em 2em 0em 2em 0em 2em 0em 2em 0em" rowspacing="3pt"> |
| | | <mtr> |
| | | <mtd></mtd> |
| | | <mtd> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | <mo>−</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | <mo>−</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>π</mi> |
| | | <mo>−</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | <mo>−</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd> |
| | | <mo>=</mo> |
| | | </mtd> |
| | | <mtd> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mn>1</mn> |
| | | <mo stretchy="false">)</mo> |
| | | <mo>−</mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mn>1</mn> |
| | | <mo stretchy="false">)</mo> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd> |
| | | <mo>=</mo> |
| | | </mtd> |
| | | <mtd> |
| | | <mn>0</mn> |
| | | <mo>.</mo> |
| | | </mtd> |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>的值. |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(20)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <div v-if="isShowAnswer20" > |
| | | |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mtable displaystyle="true" |
| | | columnalign="right left right left right left right left right left right left" |
| | | columnspacing="0em 2em 0em 2em 0em 2em 0em 2em 0em 2em 0em" rowspacing="3pt"> |
| | | <mtr> |
| | | <mtd></mtd> |
| | | <mtd> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | <mo>−</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>π</mi> |
| | | <mo>−</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd> |
| | | <mo>=</mo> |
| | | </mtd> |
| | | <mtd> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mn>1</mn> |
| | | <mo stretchy="false">)</mo> |
| | | <mo>−</mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mn>1</mn> |
| | | <mo stretchy="false">)</mo> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd> |
| | | <mo>=</mo> |
| | | </mtd> |
| | | <mtd> |
| | | <mn>0</mn> |
| | | <mo>.</mo> |
| | | </mtd> |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | </p> |
| | | </div> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 174 --> |
| | | <div class="page-box hidePage" page="181"></div> |
| | | |
| | | <!-- 175 --> |
| | | <div class="page-box" page="182"> |
| | | <div v-if="showPageList.indexOf(182) > -1"> |
| | |
| | | <p>第五单元 三角函数</p> |
| | | </li> |
| | | <li> |
| | | <p><span>175</span></p> |
| | | <p><span>175-176</span></p> |
| | | </li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>例1</b></span> 已知<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </math>, 且<i>α</i>是第四象限角,求sin<i>α</i>,tan<i>α</i>的值. |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例1</b></span> 已知<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </math>, 且<i>α</i>是第四象限角,求sin<i>α</i>,tan<i>α</i>的值. |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(21)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 因为 |
| | | <i>α</i>是第四象限角,所以sin<i>α</i><0 . |
| | | </p> |
| | | <math display="block"> |
| | | <mtable columnspacing="1em" rowspacing="4pt"> |
| | | <mtr> |
| | | <mtd> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <msqrt> |
| | | <mn>1</mn> |
| | | <mo>−</mo> |
| | | <msup> |
| | | <mi>cos</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <div v-if="isShowAnswer21" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 因为 |
| | | <i>α</i>是第四象限角,所以sin<i>α</i><0 . |
| | | </p> |
| | | <math display="block"> |
| | | <mtable columnspacing="1em" rowspacing="4pt"> |
| | | <mtr> |
| | | <mtd> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </msqrt> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <msqrt> |
| | | <mn>1</mn> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | </msqrt> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>4</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo>,</mo> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <msqrt> |
| | | <mn>1</mn> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>4</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | <msup> |
| | | <mi>cos</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </msqrt> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <msqrt> |
| | | <mn>1</mn> |
| | | <mo>−</mo> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | </msqrt> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mn>4</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>4</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </mtd> |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | <mo>,</mo> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>4</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </mrow> |
| | | <mfrac> |
| | | <mn>3</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>4</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </mtd> |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | </div> |
| | | <div class="bk"> |
| | | <div class="bj1"> |
| | | <p class="left"> |
| | |
| | | </math>.其开方后的符号是由正弦值的象限符号来确定的.同理,开方后余弦值的符号也一样. |
| | | </p> |
| | | </div> |
| | | <p> |
| | | <span class="zt-ls"><b>例2</b></span> 已知<math display="0"> |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例2</b></span> 已知<math display="0"> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>12</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </math>,且<i>α</i>是第三象限角,求sin <i>α</i>,cos <i>α</i>的值. |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(22)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <div v-if="isShowAnswer22" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | </p> |
| | | <math display="block"> |
| | | <mtext> 由 </mtext> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | |
| | | <mn>12</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </math>,且<i>α</i>是第三象限角,求sin <i>α</i>,cos <i>α</i>的值. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | </p> |
| | | <math display="block"> |
| | | <mtext> 由 </mtext> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>12</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mtext> 得, </mtext> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>12</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mtext>, 即 </mtext> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>12</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mtext>. </mtext> |
| | | </math> |
| | | <p>把①代入</p> |
| | | <math display="block"> |
| | | <msup> |
| | | <mtext> 得, </mtext> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>12</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mtext>, 即 </mtext> |
| | | <mi>sin</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>+</mo> |
| | | <msup> |
| | | <mi>cos</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mn>1</mn> |
| | | <mo>,</mo> |
| | | </math> |
| | | <p class="right">①</p> |
| | | <p>得</p> |
| | | <math display="block"> |
| | | <mtable columnspacing="1em" rowspacing="4pt"> |
| | | <mtr> |
| | | <mtd> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>12</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo>+</mo> |
| | | <msup> |
| | | <mi>cos</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mn>1</mn> |
| | | <mo>,</mo> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd> |
| | | <mfrac> |
| | | <mn>169</mn> |
| | | <mn>25</mn> |
| | | </mfrac> |
| | | <msup> |
| | | <mi>cos</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mn>1</mn> |
| | | <mo>,</mo> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd> |
| | | <msup> |
| | | <mi>cos</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>25</mn> |
| | | <mn>169</mn> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </mtd> |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | <p>因为<i>α</i>是第三象限角,所以cos<i>α</i><0.</p> |
| | | <p> |
| | | 所以<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>12</mn> |
| | | <mn>5</mn> |
| | | <mn>13</mn> |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 176 --> |
| | | <div class="page-box" page="183"> |
| | | <div v-if="showPageList.indexOf(183) > -1"> |
| | | <ul class="page-header-odd fl al-end"> |
| | | <li>176</li> |
| | | <li>数学.基础模块</li> |
| | | <li>上册</li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <p> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mtext>. </mtext> |
| | | </math> |
| | | <p>把①代入</p> |
| | | <math display="block"> |
| | | <msup> |
| | | <mi>sin</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>+</mo> |
| | | <msup> |
| | | <mi>cos</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mn>1</mn> |
| | | <mo>,</mo> |
| | | </math> |
| | | <p class="right">①</p> |
| | | <p>得</p> |
| | | <math display="block"> |
| | | <mtable columnspacing="1em" rowspacing="4pt"> |
| | | <mtr> |
| | | <mtd> |
| | | <msup> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mn>12</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo>+</mo> |
| | | <msup> |
| | | <mi>cos</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mn>1</mn> |
| | | <mo>,</mo> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd> |
| | | <mfrac> |
| | | <mn>169</mn> |
| | | <mn>25</mn> |
| | | </mfrac> |
| | | <msup> |
| | | <mi>cos</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mn>1</mn> |
| | | <mo>,</mo> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd> |
| | | <msup> |
| | | <mi>cos</mi> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>25</mn> |
| | | <mn>169</mn> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </mtd> |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | <p>因为<i>α</i>是第三象限角,所以cos<i>α</i><0.</p> |
| | | <p> |
| | | 所以<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>5</mn> |
| | | <mn>13</mn> |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | 把<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | |
| | | </mfrac> |
| | | </math>代入①式,得 |
| | | </p> |
| | | <math display="block"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>12</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>12</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo>×</mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <math display="block"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>12</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>12</mn> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo>×</mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>5</mn> |
| | | <mn>13</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>5</mn> |
| | | <mn>12</mn> |
| | | <mn>13</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>12</mn> |
| | | <mn>13</mn> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </math> |
| | | <p> |
| | | <span class="zt-ls"><b>例3</b></span> 求证sin<sup>4</sup><i>α</i>-cos<sup>4</sup><i>α</i>=2sin |
| | | <sup>2</sup><i>α</i>-1. |
| | | </p> |
| | | <p> |
| | | <b>证明</b> sin<sup>4</sup><i>α</i>-cos<sup>4</sup><i>α</i>=(sin |
| | | <sup>2</sup><i>α</i>+cos<sup>2</sup><i>α</i>)(sin<sup>2</sup><i>α</i>-cos<sup>2</sup><i>α</i>) |
| | | </p> |
| | | <p>=sin<sup>2</sup><i>α</i>-cos<sup>2</sup><i>α</i></p> |
| | | <p>=sin<sup>2</sup><i>α</i>-(1-sin<sup>2</sup><i>α</i>)</p> |
| | | <p>=2sin<sup>2</sup><i>α</i>-1.</p> |
| | | <p> |
| | | <span class="zt-ls"><b>例4</b></span> 化简<math display="0"> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>−</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>−</mo> |
| | | <mn>1</mn> |
| | | </mrow> |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | </p> |
| | | <math display="block"> |
| | | <mo>由</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mn>3</mn> |
| | | <mo>,</mo> |
| | | <mo>得</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mn>3</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>.</mo> |
| | | <mtable displaystyle="true" columnalign="right left right left right left right left right left right left" |
| | | columnspacing="0em 2em 0em 2em 0em 2em 0em 2em 0em 2em 0em" rowspacing="3pt"> |
| | | <mtr> |
| | | <mtd> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>+</mo> |
| | | <mn>3</mn> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | </mtd> |
| | | <mtd> |
| | | <mi></mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mn>3</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo stretchy="false">)</mo> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>+</mo> |
| | | <mn>3</mn> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mn>3</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo stretchy="false">)</mo> |
| | | </mrow> |
| | | </mfrac> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd></mtd> |
| | | <mtd> |
| | | <mi></mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mn>14</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mn>4</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>7</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </mtd> |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | <div class="bk"> |
| | | <div class="bj1"> |
| | | <p class="left"> |
| | | <img class="img-gn1" alt="" src="../../assets/images/tbts.jpg" /> |
| | | </p> |
| | | </div> |
| | | <p class="block"> |
| | | 方法一的运算思路是由正弦函数、余弦函数变化为正切函数求出结果,我们简称为“弦化切”;方法二的运算思路是由正切函数变化为正弦函数和余弦函数的关系后求出结果,我们简称为“切化弦”. |
| | | </p> |
| | | </div> |
| | | <p> |
| | | <span class="zt-ls"><b>例5</b></span> 已知tan<i>θ</i>=-3,求<math display="0"> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>+</mo> |
| | | <mn>3</mn> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | </math>的值. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 方法一:显然cos <i>θ</i>≠0, |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>+</mo> |
| | | <mn>3</mn> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | </mrow> |
| | | <mrow> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mo>+</mo> |
| | | <mn>3</mn> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mo>×</mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mn>3</mn> |
| | | <mo stretchy="false">)</mo> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mo>+</mo> |
| | | <mn>3</mn> |
| | | <mo>×</mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mn>3</mn> |
| | | <mo stretchy="false">)</mo> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>7</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </math> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例3</b></span> 求证sin<sup>4</sup><i>α</i>-cos<sup>4</sup><i>α</i>=2sin |
| | | <sup>2</sup><i>α</i>-1. |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(23)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p>方法二:</p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <div v-if="isShowAnswer23" > |
| | | <p> |
| | | <b>证明</b> sin<sup>4</sup><i>α</i>-cos<sup>4</sup><i>α</i>=(sin |
| | | <sup>2</sup><i>α</i>+cos<sup>2</sup><i>α</i>)(sin<sup>2</sup><i>α</i>-cos<sup>2</sup><i>α</i>) |
| | | </p> |
| | | <p>=sin<sup>2</sup><i>α</i>-cos<sup>2</sup><i>α</i></p> |
| | | <p>=sin<sup>2</sup><i>α</i>-(1-sin<sup>2</sup><i>α</i>)</p> |
| | | <p>=2sin<sup>2</sup><i>α</i>-1.</p> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例4</b></span> 化简<math display="0"> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>−</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>−</mo> |
| | | <mn>1</mn> |
| | | </mrow> |
| | | </mfrac> |
| | | </math>. |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(24)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <div v-if="isShowAnswer24" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | </p> |
| | | <math display="block"> |
| | | <mo>由</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mtable displaystyle="true" |
| | | columnalign="right left right left right left right left right left right left" |
| | | <mtable displaystyle="true" columnalign="right left right left right left right left right left right left" |
| | | columnspacing="0em 2em 0em 2em 0em 2em 0em 2em 0em 2em 0em" rowspacing="3pt"> |
| | | <mtr> |
| | | <mtd> |
| | |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | </div> |
| | | <div class="bk mt-60"> |
| | | <div class="bj1"> |
| | | <p class="left"> |
| | | <img class="img-gn1" alt="" src="../../assets/images/tbts.jpg" /> |
| | | </p> |
| | | </div> |
| | | <p class="block"> |
| | | 方法一的运算思路是由正弦函数、余弦函数变化为正切函数求出结果,我们简称为“弦化切”;方法二的运算思路是由正切函数变化为正弦函数和余弦函数的关系后求出结果,我们简称为“切化弦”. |
| | | </p> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例5</b></span> 已知tan<i>θ</i>=-3,求<math display="0"> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>+</mo> |
| | | <mn>3</mn> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | </math>的值. |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(25)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <div v-if="isShowAnswer25" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 方法一:显然cos <i>θ</i>≠0, |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>+</mo> |
| | | <mn>3</mn> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | </mrow> |
| | | <mrow> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mo>+</mo> |
| | | <mn>3</mn> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mo>×</mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mn>3</mn> |
| | | <mo stretchy="false">)</mo> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mo>+</mo> |
| | | <mn>3</mn> |
| | | <mo>×</mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mn>3</mn> |
| | | <mo stretchy="false">)</mo> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>7</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | <p>方法二:</p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo>由</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mn>3</mn> |
| | | <mo>,</mo> |
| | | <mo>得</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mn>3</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mtable displaystyle="true" |
| | | columnalign="right left right left right left right left right left right left" |
| | | columnspacing="0em 2em 0em 2em 0em 2em 0em 2em 0em 2em 0em" rowspacing="3pt"> |
| | | <mtr> |
| | | <mtd> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>+</mo> |
| | | <mn>3</mn> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | </mtd> |
| | | <mtd> |
| | | <mi></mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mn>3</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo stretchy="false">)</mo> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo>+</mo> |
| | | <mn>3</mn> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mn>3</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | <mo stretchy="false">)</mo> |
| | | </mrow> |
| | | </mfrac> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd></mtd> |
| | | <mtd> |
| | | <mi></mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mn>14</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mn>4</mn> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>θ</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>7</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </mtd> |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | </p> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 176 --> |
| | | <div class="page-box hidePage" page="183"> |
| | | </div> |
| | | <!-- 177 --> |
| | | <div class="page-box" page="184"> |
| | | <div v-if="showPageList.indexOf(184) > -1"> |
| | |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 178 --> |
| | | <div class="page-box" page="185"> |
| | | <div v-if="showPageList.indexOf(185) > -1"> |
| | |
| | | </div> |
| | | </div> |
| | | </div> |
| | | |
| | | <!-- 179 --> |
| | | <div class="page-box" page="186"> |
| | | <div v-if="showPageList.indexOf(186) > -1"> |
| | |
| | | <p><span>179</span></p> |
| | | </li> |
| | | </ul> |
| | | |
| | | <div class="padding-116"> |
| | | <p> |
| | | <span class="zt-ls"><b>例1</b></span> 求下列三角函数的值. |
| | | <p class="p-btn" > |
| | | <span><span class="zt-ls"><b>例1</b></span> 求下列三角函数的值.</span> |
| | | <span class="btn-box" @click="hadleAnswer(26)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p> |
| | | (1) |
| | | <math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>13</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | </math>;(2) |
| | | <math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | (1) |
| | | <math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mn>13</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>;(3) tan 405°. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1)<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>13</mn> |
| | | <mi>π</mi> |
| | | </math>;(2) |
| | | <math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | </math>;(3) tan 405°. |
| | | </p> |
| | | <div v-if="isShowAnswer26" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1)<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>13</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>6</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>; |
| | | </p> |
| | | <p> |
| | | (2) |
| | | <math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | <mn>1</mn> |
| | | <mn>2</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> |
| | | </math>; |
| | | </p> |
| | | <p> |
| | | (2) |
| | | <math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>−</mo> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>; |
| | | </p> |
| | | <p>(3) tan405°=tan(45°+360°)=tan45°=1.</p> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>; |
| | | </p> |
| | | <p>(3) tan405°=tan(45°+360°)=tan45°=1.</p> |
| | | </div> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | |
| | | </li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <p> |
| | | <span class="zt-ls"><b>例2</b></span> 求下列三角函数的值. |
| | | <p class="p-btn" > |
| | | <span><span class="zt-ls"><b>例2</b></span> 求下列三角函数的值. </span> |
| | | <span class="btn-box" @click="hadleAnswer(27)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p> |
| | | (1) sin 225°;(2) |
| | |
| | | </mfrac> |
| | | </math>;(3) tan 570°. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1)<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>225</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <div v-if="isShowAnswer27" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1)<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>180</mn> |
| | | <mn>225</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>+</mo> |
| | | <mo>=</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <msup> |
| | | <mn>180</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>+</mo> |
| | | <msup> |
| | | <mn>45</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>45</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>45</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>2</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>; |
| | | </p> |
| | | <p> |
| | | (2)<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | </math>; |
| | | </p> |
| | | <p> |
| | | (2)<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>; |
| | | </p> |
| | | <p> |
| | | (3)<math display="0"> |
| | | <mtable displaystyle="true" |
| | | columnalign="right left right left right left right left right left right left" |
| | | columnspacing="0em 2em 0em 2em 0em 2em 0em 2em 0em 2em 0em" rowspacing="3pt"> |
| | | <mtr> |
| | | <mtd> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>570</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>; |
| | | </p> |
| | | <p> |
| | | (3)<math display="0"> |
| | | <mtable displaystyle="true" |
| | | columnalign="right left right left right left right left right left right left" |
| | | columnspacing="0em 2em 0em 2em 0em 2em 0em 2em 0em 2em 0em" rowspacing="3pt"> |
| | | <mtr> |
| | | <mtd> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>570</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | </mtd> |
| | | <mtd> |
| | | <mi></mi> |
| | | <mo>=</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <msup> |
| | | <mn>210</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>+</mo> |
| | | <msup> |
| | | <mn>360</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </msup> |
| | | </mtd> |
| | | <mtd> |
| | | <mi></mi> |
| | | <mo>=</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>=</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>210</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>+</mo> |
| | | <msup> |
| | | <mn>360</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>210</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | <mo>=</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <msup> |
| | | <mn>180</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>+</mo> |
| | | <msup> |
| | | <mn>30</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <msup> |
| | | <mn>180</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>+</mo> |
| | | <mo>=</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>30</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>30</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd></mtd> |
| | | <mtd> |
| | | <mi></mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd></mtd> |
| | | <mtd> |
| | | <mi></mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </mtd> |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | </p> |
| | | </mfrac> |
| | | </mtd> |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | </p> |
| | | </div> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | |
| | | 利用公式三,可以把负角的三角函数转化为正角的三角函数. |
| | | </p> |
| | | </div> |
| | | <p> |
| | | <span class="zt-ls"><b>例3</b></span> 求下列三角函数的值. |
| | | <p class="p-btn" > |
| | | <span><span class="zt-ls"><b>例3</b></span> 求下列三角函数的值.</span> |
| | | <span class="btn-box" @click="hadleAnswer(28)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p> |
| | | (1) sin(-45°);(2) cos(-390°);(3) |
| | |
| | | <mo stretchy="false">)</mo> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(1)</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <div v-if="isShowAnswer28" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(1)</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <msup> |
| | | <mn>45</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>45</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>45</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>2</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>;</mo> |
| | | </math> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(2)</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>2</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>;</mo> |
| | | </math> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(2)</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <msup> |
| | | <mn>390</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>390</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>390</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <msup> |
| | | <mn>30</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>+</mo> |
| | | <msup> |
| | | <mn>360</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>30</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>+</mo> |
| | | <msup> |
| | | <mn>360</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>30</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>;</mo> |
| | | </math> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(3)</mo> |
| | | <mtable displaystyle="true" |
| | | columnalign="right left right left right left right left right left right left" |
| | | columnspacing="0em 2em 0em 2em 0em 2em 0em 2em 0em 2em 0em" rowspacing="3pt"> |
| | | <mtr> |
| | | <mtd> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>;</mo> |
| | | </math> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(3)</mo> |
| | | <mtable displaystyle="true" |
| | | columnalign="right left right left right left right left right left right left" |
| | | columnspacing="0em 2em 0em 2em 0em 2em 0em 2em 0em 2em 0em" rowspacing="3pt"> |
| | | <mtr> |
| | | <mtd> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>16</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </mtd> |
| | | <mtd> |
| | | <mi></mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>16</mn> |
| | |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </mtd> |
| | | <mtd> |
| | | <mi></mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>16</mn> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mn>4</mn> |
| | | <mi>π</mi> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mn>4</mn> |
| | | <mi>π</mi> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd></mtd> |
| | | <mtd> |
| | | <mi></mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd></mtd> |
| | | <mtd> |
| | | <mi></mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | </mtd> |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | </p> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | </mtd> |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | </p> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | |
| | | <p> |
| | | 公式一至公式四统称为三角函数的诱导公式.利用这些公式可以把任意角的三角函数转化为锐角三角函数. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>例4</b></span> 求下列三角函数的值. |
| | | <p class="p-btn" > |
| | | <span><span class="zt-ls"><b>例4</b></span> 求下列三角函数的值.</span> |
| | | <span class="btn-box" @click="hadleAnswer(29)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p> |
| | | (1) cos 135°;(2) |
| | |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(1)</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>135</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <div v-if="isShowAnswer29" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(1)</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>180</mn> |
| | | <mn>135</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <msup> |
| | | <mn>180</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>−</mo> |
| | | <msup> |
| | | <mn>45</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>45</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <msup> |
| | | <mn>45</mn> |
| | | <mrow> |
| | | <mo>∘</mo> |
| | | </mrow> |
| | | </msup> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>2</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>;</mo> |
| | | </math> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(2)</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>8</mn> |
| | | </mfrac> |
| | | <mo>;</mo> |
| | | </math> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(2)</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>8</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>=</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>2</mn> |
| | |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | <mo>=</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mi>π</mi> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mi>π</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mo>;</mo> |
| | | </math> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(3)</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>11</mn> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mo>;</mo> |
| | | </math> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mo stretchy="false">(3)</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>11</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mi>π</mi> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mi>π</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>2</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>例5</b></span> 化简:<math display="0"> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | <mo>−</mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">)</mo> |
| | | <mo>⋅</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">)</mo> |
| | | <mo>⋅</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | <mo>−</mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">)</mo> |
| | | <mo>⋅</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mi>α</mi> |
| | | <mo>−</mo> |
| | | <mi>π</mi> |
| | | <mo stretchy="false">)</mo> |
| | | </mrow> |
| | | </mfrac> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mtable displaystyle="true" |
| | | columnalign="right left right left right left right left right left right left" |
| | | columnspacing="0em 2em 0em 2em 0em 2em 0em 2em 0em 2em 0em" rowspacing="3pt"> |
| | | <mtr> |
| | | <mtd> |
| | | <mtext> 原式 </mtext> |
| | | </mtd> |
| | | <mtd> |
| | | <mi></mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>⋅</mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">)</mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">)</mo> |
| | | </mrow> |
| | | </mfrac> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd></mtd> |
| | | <mtd> |
| | | <mi></mi> |
| | | <mo>=</mo> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例5</b></span> 化简:<math display="0"> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>⋅</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>⋅</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>⋅</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | </mrow> |
| | | </mfrac> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd></mtd> |
| | | <mtd> |
| | | <mi></mi> |
| | | <mo>=</mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">)</mo> |
| | | <mo>⋅</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">)</mo> |
| | | <mo>⋅</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | <mo>−</mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">)</mo> |
| | | <mo>⋅</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mi>α</mi> |
| | | <mo>.</mo> |
| | | </mtd> |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | <mo>−</mo> |
| | | <mi>π</mi> |
| | | <mo stretchy="false">)</mo> |
| | | </mrow> |
| | | </mfrac> |
| | | </math> |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(30)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <div v-if="isShowAnswer30" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | </p> |
| | | <p class="left1"> |
| | | <math display=""> |
| | | <mtable displaystyle="true" |
| | | columnalign="right left right left right left right left right left right left" |
| | | columnspacing="0em 2em 0em 2em 0em 2em 0em 2em 0em 2em 0em" rowspacing="3pt"> |
| | | <mtr> |
| | | <mtd> |
| | | <mtext> 原式 </mtext> |
| | | </mtd> |
| | | <mtd> |
| | | <mi></mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>⋅</mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">)</mo> |
| | | </mrow> |
| | | <mrow> |
| | | <mo>−</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">)</mo> |
| | | <mo stretchy="false">(</mo> |
| | | <mo>−</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo stretchy="false">)</mo> |
| | | </mrow> |
| | | </mfrac> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd></mtd> |
| | | <mtd> |
| | | <mi></mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>⋅</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>⋅</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>⋅</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | </mrow> |
| | | </mfrac> |
| | | </mtd> |
| | | </mtr> |
| | | <mtr> |
| | | <mtd></mtd> |
| | | <mtd> |
| | | <mi></mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | <mrow> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | </mrow> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>α</mi> |
| | | <mo>.</mo> |
| | | </mtd> |
| | | </mtr> |
| | | </mtable> |
| | | </math> |
| | | </p> |
| | | </div> |
| | | <p><b>归纳总结</b></p> |
| | | <p> |
| | | 利用诱导公式,把任意角的三角函数值转化为锐角的三角函数值的一般步骤为: |
| | |
| | | <p>第五单元 三角函数</p> |
| | | </li> |
| | | <li> |
| | | <p><span>185</span></p> |
| | | <p><span>185-186</span></p> |
| | | </li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | |
| | | <p> |
| | | <span class="zt-ls"><b>例6</b></span> 利用科学计算器计算.(结果精确到0.01) |
| | | </p> |
| | | <p> |
| | | (1) sin 63°52′41″;(2)<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math>;(3) |
| | | <math display="0"> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <p class="p-btn" > |
| | | <span>(1) sin 63°52′41″;</span> |
| | | <span class="btn-box" @click="hadleAnswer(31)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <div v-if="isShowAnswer31" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) |
| | | 先将精确度设置为0.01,再将科学计算器设置为角度计算模式,然后依次按下列各键: |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0197-1.jpg" /> |
| | | </p> |
| | | <p>结果显示:</p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0197-2.jpg" /> |
| | | </p> |
| | | <p>所以 sin 63°52′41″≈0.90.</p> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span> |
| | | (2)<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>6</mn> |
| | | <mn>4</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>. |
| | | </math>; |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(32)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | <!-- 186 --> |
| | | <div class="page-box" page="193"> |
| | | <div v-if="showPageList.indexOf(193) > -1"> |
| | | <ul class="page-header-odd fl al-end"> |
| | | <li>186</li> |
| | | <li>数学.基础模块</li> |
| | | <li>上册</li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) |
| | | 先将精确度设置为0.01,再将科学计算器设置为角度计算模式,然后依次按下列各键: |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0197-1.jpg" /> |
| | | </p> |
| | | <p>结果显示:</p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0197-2.jpg" /> |
| | | </p> |
| | | <p>所以 sin 63°52′41″≈0.90.</p> |
| | | <p> |
| | | (2) |
| | | 先将精确度设置为0.01,再将科学计算器设置为弧度计算模式,然后依次按下列各键: |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0197-3.jpg" /> |
| | | </p> |
| | | <p>结果显示:</p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0197-4.jpg" /> |
| | | </p> |
| | | <p> |
| | | 所以 |
| | | <math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>4</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mn>0.50</mn> |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | <p> |
| | | (3) |
| | | 先将精确度设置为0.01,再将科学计算器设置为弧度计算模式,然后依次按下列各键: |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0197-6.jpg" /> |
| | | </p> |
| | | <p>结果显示:</p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0197-7.jpg" /> |
| | | </p> |
| | | <p> |
| | | 所以<math display="0"> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <div v-if="isShowAnswer32" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(2) |
| | | 先将精确度设置为0.01,再将科学计算器设置为弧度计算模式,然后依次按下列各键: |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0197-3.jpg" /> |
| | | </p> |
| | | <p>结果显示:</p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0197-4.jpg" /> |
| | | </p> |
| | | <p> |
| | | 所以 |
| | | <math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>6</mn> |
| | | <mn>4</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>≈</mo> |
| | | <mo>−</mo> |
| | | <mn>0.73</mn> |
| | | <mo>.</mo> |
| | | </math> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mn>0.50</mn> |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span> |
| | | (3) |
| | | <math display="0"> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>6</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>. |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(33)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <div v-if="isShowAnswer33" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | (3) |
| | | 先将精确度设置为0.01,再将科学计算器设置为弧度计算模式,然后依次按下列各键: |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0197-6.jpg" /> |
| | | </p> |
| | | <p>结果显示:</p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0197-7.jpg" /> |
| | | </p> |
| | | <p> |
| | | 所以<math display="0"> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>6</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>≈</mo> |
| | | <mo>−</mo> |
| | | <mn>0.73</mn> |
| | | <mo>.</mo> |
| | | </math> |
| | | </p> |
| | | </div> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | <!-- 186 --> |
| | | <div class="page-box hidePage" page="193"> |
| | | </div> |
| | | <!-- 187 --> |
| | | <div class="page-box" page="194"> |
| | |
| | | <p> |
| | | <span class="zt-ls"><b>例1</b></span> 用“五点法”画出下列函数在区间[0,2π]内的简图. |
| | | </p> |
| | | <p>(1) <i>y</i>=-sin<i>x</i>;(2) <i>y</i>=1+sin<i>x</i>.</p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) 列表(表5-6). |
| | | <p class="p-btn" > |
| | | <span> |
| | | (1) <i>y</i>=-sin<i>x</i>; |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(34)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p class="img">表5-6</p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0201-2.jpg" /> |
| | | <div v-if="isShowAnswer34" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) 列表(表5-6). |
| | | </p> |
| | | <p class="img">表5-6</p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0201-2.jpg" /> |
| | | </p> |
| | | <p> |
| | | 描点连线得<i>y</i>=-sin<i>x</i>在区间[0,2π]内的简图,如图5-27所示. |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-d" alt="" src="../../assets/images/0201-3.jpg" /> |
| | | </p> |
| | | <p class="img">图5-27</p> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span>(2) <i>y</i>=1+sin<i>x</i>.</span> |
| | | <span class="btn-box" @click="hadleAnswer(35)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p> |
| | | 描点连线得<i>y</i>=-sin<i>x</i>在区间[0,2π]内的简图,如图5-27所示. |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-d" alt="" src="../../assets/images/0201-3.jpg" /> |
| | | </p> |
| | | <p class="img">图5-27</p> |
| | | <p>(2) 列表(表5-7).</p> |
| | | <p class="img">表5-7</p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0201-4.jpg" /> |
| | | </p> |
| | | <p> |
| | | 描点连线得<i>y</i>=1+sin<i>x</i>在区间[0,2π]内的简图,如图5-28所示. |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-d" alt="" src="../../assets/images/0201-5.jpg" /> |
| | | </p> |
| | | <p class="img">图5-28</p> |
| | | <div v-if="isShowAnswer35" > |
| | | <p><span class="zt-ls"><b>解</b></span>(2) 列表(表5-7).</p> |
| | | <p class="img">表5-7</p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0201-4.jpg" /> |
| | | </p> |
| | | <p> |
| | | 描点连线得<i>y</i>=1+sin<i>x</i>在区间[0,2π]内的简图,如图5-28所示. |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-d" alt="" src="../../assets/images/0201-5.jpg" /> |
| | | </p> |
| | | <p class="img">图5-28</p> |
| | | </div> |
| | | <iframe src="https://www.geogebra.org/calculator" frameborder="0" class="iframe-box"></iframe> |
| | | </div> |
| | | </div> |
| | | </div> |
| | |
| | | <p> |
| | | 因为sin(-<i>x</i>)=-sin<i>x</i>,所以<i>y</i>=sin<i>x</i>是奇函数,其图像关于原点对称. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>例1</b></span> 已知<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mo>−</mo> |
| | | <mi>a</mi> |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>,求<i>a</i>的取值范围. |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例1</b></span> 已知<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mo>−</mo> |
| | | <mi>a</mi> |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>,求<i>a</i>的取值范围. |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(36)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 因为 -1≤sin<i>x</i>≤1, |
| | | </p> |
| | | <p> |
| | | 所以 <math display="0"> |
| | | <mo>−</mo> |
| | | <mn>1</mn> |
| | | <mo>⩽</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mo>−</mo> |
| | | <mi>a</mi> |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>⩽</mo> |
| | | <mn>1</mn> |
| | | </math>, |
| | | </p> |
| | | <p>解得 1≤<i>a</i>≤5.</p> |
| | | <div v-if="isShowAnswer36" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 因为 -1≤sin<i>x</i>≤1, |
| | | </p> |
| | | <p> |
| | | 所以 <math display="0"> |
| | | <mo>−</mo> |
| | | <mn>1</mn> |
| | | <mo>⩽</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mo>−</mo> |
| | | <mi>a</mi> |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>⩽</mo> |
| | | <mn>1</mn> |
| | | </math>, |
| | | </p> |
| | | <p>解得 1≤<i>a</i>≤5.</p> |
| | | </div> |
| | | <p> |
| | | <span class="zt-ls"><b>例2</b></span> 求使下列函数取得最大值、最小值的<i>x</i>的集合,并求出这些函数的最大值、最小值. |
| | | </p> |
| | | <p>(1) <i>y</i>=3+sin<i>x</i>;(2) <i>y</i>=-2sin<i>x</i>.</p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) |
| | | 使函数<i>y</i>=3+sin<i>x</i>取得最大值的<i>x</i>的集合,就是使函数<i>y</i>=sin<i>x</i>取得最大值的<i>x</i>的集合<math display="0"> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">{</mo> |
| | | <mi>x</mi> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">|</mo> |
| | | <mstyle scriptlevel="0"> |
| | | <mspace width="thinmathspace"></mspace> |
| | | </mstyle> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mn>2</mn> |
| | | <mi>k</mi> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE" fence="true" stretchy="true" symmetric="true"></mo> |
| | | </mrow> |
| | | <mo>,</mo> |
| | | <mi>k</mi> |
| | | <mo>∈</mo> |
| | | <mrow> |
| | | <mi mathvariant="bold">Z</mi> |
| | | </mrow> |
| | | <mo data-mjx-texclass="CLOSE">}</mo> |
| | | </mrow> |
| | | </math>.这时函数<i>y</i>=3+sin<i>x</i>的最大值为<i>y</i>=3+1=4. |
| | | <p class="p-btn" > |
| | | <span> |
| | | (1) <i>y</i>=3+sin<i>x</i>; |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(37)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p> |
| | | 使函数<i>y</i>=3+sin<i>x</i>取得最小值的<i>x</i>的集合,就是使函数<i>y</i>=sin<i>x</i>取得最小值的<i>x</i>的集合<math display="0"> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">{</mo> |
| | | <mi>x</mi> |
| | | <div v-if="isShowAnswer37" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) |
| | | 使函数<i>y</i>=3+sin<i>x</i>取得最大值的<i>x</i>的集合,就是使函数<i>y</i>=sin<i>x</i>取得最大值的<i>x</i>的集合<math display="0"> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">|</mo> |
| | | <mstyle scriptlevel="0"> |
| | | <mspace width="thinmathspace"></mspace> |
| | | </mstyle> |
| | | <mo data-mjx-texclass="OPEN">{</mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mn>2</mn> |
| | | <mi>k</mi> |
| | | <mi>π</mi> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">|</mo> |
| | | <mstyle scriptlevel="0"> |
| | | <mspace width="thinmathspace"></mspace> |
| | | </mstyle> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE" fence="true" stretchy="true" symmetric="true"></mo> |
| | | <mi>k</mi> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE" fence="true" stretchy="true" symmetric="true"></mo> |
| | | </mrow> |
| | | <mo>,</mo> |
| | | <mi>k</mi> |
| | | <mo>∈</mo> |
| | | <mrow> |
| | | <mi mathvariant="bold">Z</mi> |
| | | </mrow> |
| | | <mo data-mjx-texclass="CLOSE">}</mo> |
| | | </mrow> |
| | | <mo>,</mo> |
| | | <mi>k</mi> |
| | | <mo>∈</mo> |
| | | <mrow> |
| | | <mi mathvariant="bold">Z</mi> |
| | | </mrow> |
| | | <mo data-mjx-texclass="CLOSE">}</mo> |
| | | </mrow> |
| | | </math>.这时函数<i>y</i>=3+sin<i>x</i>的最小值为<i>y</i>=3+(-1)=2. |
| | | </p> |
| | | <p> |
| | | (2) |
| | | 使函数<i>y</i>=-2sin<i>x</i>取得最大值的<i>x</i>的集合,就是使函数<i>y</i>=sin<i>x</i>取得最小值的<i>x</i>的集合<math display="0"> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">{</mo> |
| | | <mi>x</mi> |
| | | </math>.这时函数<i>y</i>=3+sin<i>x</i>的最大值为<i>y</i>=3+1=4. |
| | | </p> |
| | | <p> |
| | | 使函数<i>y</i>=3+sin<i>x</i>取得最小值的<i>x</i>的集合,就是使函数<i>y</i>=sin<i>x</i>取得最小值的<i>x</i>的集合<math display="0"> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">|</mo> |
| | | <mstyle scriptlevel="0"> |
| | | <mspace width="thinmathspace"></mspace> |
| | | </mstyle> |
| | | <mo data-mjx-texclass="OPEN">{</mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mn>2</mn> |
| | | <mi>k</mi> |
| | | <mi>π</mi> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">|</mo> |
| | | <mstyle scriptlevel="0"> |
| | | <mspace width="thinmathspace"></mspace> |
| | | </mstyle> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE" fence="true" stretchy="true" symmetric="true"></mo> |
| | | <mi>k</mi> |
| | | <mi>π</mi> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE" fence="true" stretchy="true" symmetric="true"></mo> |
| | | </mrow> |
| | | <mo>,</mo> |
| | | <mi>k</mi> |
| | | <mo>∈</mo> |
| | | <mrow> |
| | | <mi mathvariant="bold">Z</mi> |
| | | </mrow> |
| | | <mo data-mjx-texclass="CLOSE">}</mo> |
| | | </mrow> |
| | | <mo>,</mo> |
| | | <mi>k</mi> |
| | | <mo>∈</mo> |
| | | <mrow> |
| | | <mi mathvariant="bold">Z</mi> |
| | | </mrow> |
| | | <mo data-mjx-texclass="CLOSE">}</mo> |
| | | </mrow> |
| | | </math>.这时函数<i>y</i>=-2sin<i>x</i>的最大值为<i>y</i>=-2×(-1)=2. |
| | | </math>.这时函数<i>y</i>=3+sin<i>x</i>的最小值为<i>y</i>=3+(-1)=2. |
| | | </p> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span> |
| | | (2) <i>y</i>=-2sin<i>x</i>. |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(38)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p> |
| | | 使函数<i>y</i>=-2sin<i>x</i>取得最小值的<i>x</i>的集合,就是使函数<i>y</i>=sin<i>x</i>取得最大值的<i>x</i>的集合<math display="0"> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">{</mo> |
| | | <mi>x</mi> |
| | | <div v-if="isShowAnswer38" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(2) |
| | | 使函数<i>y</i>=-2sin<i>x</i>取得最大值的<i>x</i>的集合,就是使函数<i>y</i>=sin<i>x</i>取得最小值的<i>x</i>的集合<math display="0"> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">|</mo> |
| | | <mstyle scriptlevel="0"> |
| | | <mspace width="thinmathspace"></mspace> |
| | | </mstyle> |
| | | <mo data-mjx-texclass="OPEN">{</mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mn>2</mn> |
| | | <mi>k</mi> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">|</mo> |
| | | <mstyle scriptlevel="0"> |
| | | <mspace width="thinmathspace"></mspace> |
| | | </mstyle> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE" fence="true" stretchy="true" symmetric="true"></mo> |
| | | <mi>k</mi> |
| | | <mi>π</mi> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE" fence="true" stretchy="true" symmetric="true"></mo> |
| | | </mrow> |
| | | <mo>,</mo> |
| | | <mi>k</mi> |
| | | <mo>∈</mo> |
| | | <mrow> |
| | | <mi mathvariant="bold">Z</mi> |
| | | </mrow> |
| | | <mo data-mjx-texclass="CLOSE">}</mo> |
| | | </mrow> |
| | | <mo>,</mo> |
| | | <mi>k</mi> |
| | | <mo>∈</mo> |
| | | <mrow> |
| | | <mi mathvariant="bold">Z</mi> |
| | | </math>.这时函数<i>y</i>=-2sin<i>x</i>的最大值为<i>y</i>=-2×(-1)=2. |
| | | </p> |
| | | <p> |
| | | 使函数<i>y</i>=-2sin<i>x</i>取得最小值的<i>x</i>的集合,就是使函数<i>y</i>=sin<i>x</i>取得最大值的<i>x</i>的集合<math display="0"> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">{</mo> |
| | | <mi>x</mi> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">|</mo> |
| | | <mstyle scriptlevel="0"> |
| | | <mspace width="thinmathspace"></mspace> |
| | | </mstyle> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mn>2</mn> |
| | | <mi>k</mi> |
| | | <mi>π</mi> |
| | | <mo>+</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE" fence="true" stretchy="true" symmetric="true"></mo> |
| | | </mrow> |
| | | <mo>,</mo> |
| | | <mi>k</mi> |
| | | <mo>∈</mo> |
| | | <mrow> |
| | | <mi mathvariant="bold">Z</mi> |
| | | </mrow> |
| | | <mo data-mjx-texclass="CLOSE">}</mo> |
| | | </mrow> |
| | | <mo data-mjx-texclass="CLOSE">}</mo> |
| | | </mrow> |
| | | </math>.这时函数<i>y</i>=-2sin<i>x</i>的最小值为<i>y</i>=-2×1=-2. |
| | | </p> |
| | | </math>.这时函数<i>y</i>=-2sin<i>x</i>的最小值为<i>y</i>=-2×1=-2. |
| | | </p> |
| | | </div> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | |
| | | <p> |
| | | <b>例</b> 不求值,利用正弦函数的单调性,比较下列各对正弦值的大小. |
| | | </p> |
| | | <p> |
| | | (1)<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <p class="p-btn" > |
| | | <span> |
| | | (1)<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | </math>与<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | </math>与<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math>;(2)<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>9</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>与<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>10</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>. |
| | | </math>; |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(39)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) 因为 <math display="0"> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>, |
| | | </p> |
| | | <p> |
| | | 而<i>y</i>=sin <i>x</i> 在<math display="0"> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">[</mo> |
| | | <div v-if="isShowAnswer39" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) 因为 <math display="0"> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>,</mo> |
| | | <mo><</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">]</mo> |
| | | </mrow> |
| | | </math>上是减函数,所以 |
| | | </p> |
| | | <math display="block"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | </math>, |
| | | </p> |
| | | <p> |
| | | 而<i>y</i>=sin <i>x</i> 在<math display="0"> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">[</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>,</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">]</mo> |
| | | </mrow> |
| | | </math>上是减函数,所以 |
| | | </p> |
| | | <math display="block"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>2</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mtext>. </mtext> |
| | | </math> |
| | | </mfrac> |
| | | <mtext>. </mtext> |
| | | </math> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span> |
| | | (2)<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>9</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>与<math display="0"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>10</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>. |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(40)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <div v-if="isShowAnswer40" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(2) 因为 <math display="0"> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>9</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>10</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mn>0</mn> |
| | | </math>, |
| | | </p> |
| | | <p> |
| | | 而<i>y</i>=sin <i>x</i>在<math display="0"> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">[</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>,</mo> |
| | | <mn>0</mn> |
| | | <mo data-mjx-texclass="CLOSE">]</mo> |
| | | </mrow> |
| | | </math>上是增函数,所以 |
| | | </p> |
| | | <math display="block"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>9</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo><</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>10</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | |
| | | <li>上册</li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <p> |
| | | (2) 因为 <math display="0"> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>9</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>10</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mn>0</mn> |
| | | </math>, |
| | | </p> |
| | | <p> |
| | | 而<i>y</i>=sin <i>x</i>在<math display="0"> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">[</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>,</mo> |
| | | <mn>0</mn> |
| | | <mo data-mjx-texclass="CLOSE">]</mo> |
| | | </mrow> |
| | | </math>上是增函数,所以 |
| | | </p> |
| | | <math display="block"> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>9</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo><</mo> |
| | | <mi>sin</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>10</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | |
| | | <p class="img">图5-32</p> |
| | | </div> |
| | | <p><b>例</b> 用“五点法”画出下列函数在区间[0,2π]内的简图.</p> |
| | | <p>(1) <i>y</i>=2cos <i>x</i>;(2) <i>y</i>=-1+cos <i>x</i>.</p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) 列表(表5-10). |
| | | <p class="p-btn" > |
| | | <span>(1) <i>y</i>=2cos <i>x</i>;</span> |
| | | <span class="btn-box" @click="hadleAnswer(41)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p class="img">表5-10</p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0207-5.jpg" /> |
| | | <p class="p-btn" > |
| | | <span>(2) <i>y</i>=-1+cos <i>x</i>.</span> |
| | | <span class="btn-box" @click="hadleAnswer(42)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <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> |
| | | <iframe src="https://www.geogebra.org/calculator" frameborder="0" class="iframe-box"></iframe> |
| | | <div v-if="isShowAnswer41" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) 列表(表5-10). |
| | | </p> |
| | | <p class="img">表5-10</p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0207-5.jpg" /> |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-f" alt="" src="../../assets/images/0207-6.jpg" /> |
| | | </p> |
| | | <p class="img">图5-33</p> |
| | | <p>描点连线得<i>y</i>=2cos <i>x</i>在区间[0,2π]</p> |
| | | <p>内的简图,如图5-33所示.</p> |
| | | </div> |
| | | <div v-if="isShowAnswer42" > |
| | | <p>(2) 列表(表5-11).</p> |
| | | <p class="img">表5-11</p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0208-1.jpg" /> |
| | | </p> |
| | | <p> |
| | | 描点连线得<i>y</i>=-1+cos |
| | | <i>x</i>在区间[0,2π]内的简图,如图5-34所示. |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-d" alt="" src="../../assets/images/0208-2.jpg" /> |
| | | </p> |
| | | <p class="img">图5-34</p> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | |
| | | </li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <p>(2) 列表(表5-11).</p> |
| | | <p class="img">表5-11</p> |
| | | <p class="center"> |
| | | <img class="img-a" alt="" src="../../assets/images/0208-1.jpg" /> |
| | | </p> |
| | | <p> |
| | | 描点连线得<i>y</i>=-1+cos |
| | | <i>x</i>在区间[0,2π]内的简图,如图5-34所示. |
| | | </p> |
| | | <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> |
| | |
| | | 余弦函数<i>y</i>=cos |
| | | <i>x</i>在每一个区间[2<i>k</i>π,2<i>k</i>π+π](<i>k</i>∈<b>Z</b>)上都是减函数,其值由1减小到-1;在每一个区间[2<i>k</i>π+π,2<i>k</i>π+2π](<i>k</i>∈<b>Z</b>)上都是增函数,其值由-1增大到1. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>例1</b></span> 求函数<i>y</i>=-1+cos <i>x</i>的最大值、最小值、最小正周期及值域. |
| | | <p class="p-btn" > |
| | | <span><span class="zt-ls"><b>例1</b></span> 求函数<i>y</i>=-1+cos <i>x</i>的最大值、最小值、最小正周期及值域.</span> |
| | | <span class="btn-box" @click="hadleAnswer(43)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | 当<i>x</i>=2<i>k</i>π(<i>k</i>∈<b>Z</b>)时,函数<i>y</i>=-1+cos |
| | | <i>x</i>的最大值为<i>y</i>=1-1=0; |
| | | </p> |
| | | <p> |
| | | 当<i>x</i>=2<i>k</i>π+π(<i>k</i>∈<i>Z</i>)时,函数<i>y</i>=-1+cos |
| | | <i>x</i>的最小值为<i>y</i>=-1-1=-2; |
| | | </p> |
| | | <p> |
| | | 函数<i>y</i>=-1+cos <i>x</i>的最小正周期为2π;函数<i>y</i>=-1+cos |
| | | <i>x</i>的值域为[-2,0]. |
| | | </p> |
| | | <div v-if="isShowAnswer43" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | 当<i>x</i>=2<i>k</i>π(<i>k</i>∈<b>Z</b>)时,函数<i>y</i>=-1+cos |
| | | <i>x</i>的最大值为<i>y</i>=1-1=0; |
| | | </p> |
| | | <p> |
| | | 当<i>x</i>=2<i>k</i>π+π(<i>k</i>∈<i>Z</i>)时,函数<i>y</i>=-1+cos |
| | | <i>x</i>的最小值为<i>y</i>=-1-1=-2; |
| | | </p> |
| | | <p> |
| | | 函数<i>y</i>=-1+cos <i>x</i>的最小正周期为2π;函数<i>y</i>=-1+cos |
| | | <i>x</i>的值域为[-2,0]. |
| | | </p> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | |
| | | <p> |
| | | <span class="zt-ls"><b>例2</b></span> 不求值,利用余弦函数的单调性,比较下列各对余弦值的大小. |
| | | </p> |
| | | <p> |
| | | (1) |
| | | <math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>6</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | </math>与<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <p class="p-btn" > |
| | | <span> |
| | | (1) |
| | | <math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>6</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | </math>;(2) |
| | | <math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>7</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>与<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | </math>与<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>8</mn> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>. |
| | | </math>; |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(44)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) 因为<math display="0"> |
| | | <mi>π</mi> |
| | | <mo><</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>6</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>,而函数<i>y</i>=cos <i>x</i>在<math display="0"> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">[</mo> |
| | | <div v-if="isShowAnswer44" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(1) 因为<math display="0"> |
| | | <mi>π</mi> |
| | | <mo>,</mo> |
| | | <mo><</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>6</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">]</mo> |
| | | </mrow> |
| | | </math>上是增函数,所以 |
| | | </p> |
| | | <math display="block"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>6</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | </math>,而函数<i>y</i>=cos <i>x</i>在<math display="0"> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">[</mo> |
| | | <mi>π</mi> |
| | | <mo>,</mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>3</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">]</mo> |
| | | </mrow> |
| | | </math>上是增函数,所以 |
| | | </p> |
| | | <math display="block"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>6</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>5</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </math> |
| | | <p> |
| | | (2)<math display="0"> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mrow> |
| | | <mn>5</mn> |
| | | <mi>π</mi> |
| | | </mrow> |
| | | <mn>4</mn> |
| | | </mfrac> |
| | | <mo>.</mo> |
| | | </math> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span> |
| | | (2) |
| | | <math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>7</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>与<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>8</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>. |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(45)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <div v-if="isShowAnswer45" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span>(2)<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>7</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>7</mn> |
| | | </mfrac> |
| | | </math>,<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>8</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>8</mn> |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | 因为<math display="0"> |
| | | <mn>0</mn> |
| | | <mo><</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>8</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>7</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>,而函数<i>y</i>=cos <i>x</i>在0,<math display="0"> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">[</mo> |
| | | <mn>0</mn> |
| | | <mo>,</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">]</mo> |
| | | </mrow> |
| | | </math>上是减函数,所以<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>7</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>8</mn> |
| | | </mfrac> |
| | | </math>,即 |
| | | </p> |
| | | <math display="block"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>7</mn> |
| | | </mfrac> |
| | | </math>,<math display="0"> |
| | | <mo><</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>8</mn> |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | 因为<math display="0"> |
| | | <mn>0</mn> |
| | | <mo><</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>8</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>7</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>,而函数<i>y</i>=cos <i>x</i>在0,<math display="0"> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">[</mo> |
| | | <mn>0</mn> |
| | | <mo>,</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">]</mo> |
| | | </mrow> |
| | | </math>上是减函数,所以<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>7</mn> |
| | | </mfrac> |
| | | <mo><</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>8</mn> |
| | | </mfrac> |
| | | </math>,即 |
| | | </p> |
| | | <math display="block"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>7</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo><</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>8</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>.</mo> |
| | | </math> |
| | | <mo>.</mo> |
| | | </math> |
| | | </div> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>例1</b></span> 已知<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例1</b></span> 已知<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <msqrt> |
| | | <mn>2</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </msqrt> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>,且<i>x</i>∈[0,2π] ,求<i>x</i>的值. |
| | | </mfrac> |
| | | </math>,且<i>x</i>∈[0,2π] ,求<i>x</i>的值. |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(46)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p> |
| | | <p v-if="isShowAnswer46"> |
| | | <span class="zt-ls"><b>解</b></span> 因为<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>例2</b></span> 已知<math display="0"> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例2</b></span> 已知<math display="0"> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>≠</mo> |
| | | <mfrac> |
| | | <mo>=</mo> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mi>x</mi> |
| | | <mo>≠</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>+</mo> |
| | | <mi>k</mi> |
| | | <mi>π</mi> |
| | | <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> |
| | | <mo>,</mo> |
| | | <mi>k</mi> |
| | | <mo>∈</mo> |
| | | <mrow> |
| | | <mi mathvariant="bold">Z</mi> |
| | | </mrow> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>,且0°≤<i>x</i>≤360°,求<i>x</i>的值. |
| | | </math>,且0°≤<i>x</i>≤360°,求<i>x</i>的值. |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(47)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 因为<math display="0"> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mo>></mo> |
| | | <mn>0</mn> |
| | | </math>,所以<i>x</i>是第一或第三象限角. |
| | | </p> |
| | | <p> |
| | | 由<math display="0"> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mn>60</mn> |
| | | <mrow> |
| | | <mo>°</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | </math>可知,符合条件的第一象限角是<i>x</i>=60°. |
| | | </p> |
| | | <p> |
| | | 又因为<math display="0"> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mn>180</mn> |
| | | <mrow> |
| | | <mo>°</mo> |
| | | </mrow> |
| | | <mo>+</mo> |
| | | <div v-if="isShowAnswer47" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 因为<math display="0"> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | <mo>></mo> |
| | | <mn>0</mn> |
| | | </math>,所以<i>x</i>是第一或第三象限角. |
| | | </p> |
| | | <p> |
| | | 由<math display="0"> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mn>60</mn> |
| | | <mrow> |
| | | <mo>°</mo> |
| | | </mrow> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mn>60</mn> |
| | | <mrow> |
| | | <mo>°</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | </math>, |
| | | </p> |
| | | <p>所以符合条件的第三象限角是<i>x</i>=180°+60°=240°.</p> |
| | | <p>所以<i>x</i>=60°或<i>x</i>=240°.</p> |
| | | <mo>=</mo> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | </math>可知,符合条件的第一象限角是<i>x</i>=60°. |
| | | </p> |
| | | <p> |
| | | 又因为<math display="0"> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mn>180</mn> |
| | | <mrow> |
| | | <mo>°</mo> |
| | | </mrow> |
| | | <mo>+</mo> |
| | | <mn>60</mn> |
| | | <mrow> |
| | | <mo>°</mo> |
| | | </mrow> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>tan</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mn>60</mn> |
| | | <mrow> |
| | | <mo>°</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <msqrt> |
| | | <mn>3</mn> |
| | | </msqrt> |
| | | </math>, |
| | | </p> |
| | | <p>所以符合条件的第三象限角是<i>x</i>=180°+60°=240°.</p> |
| | | <p>所以<i>x</i>=60°或<i>x</i>=240°.</p> |
| | | </div> |
| | | <div class="bk"> |
| | | <div class="bj1"> |
| | | <p class="left"> |
| | |
| | | 根据<i>x</i>所在的象限和诱导公式,写出满足题目给定范围的<i>x</i>的值. |
| | | </p> |
| | | </div> |
| | | <p> |
| | | <span class="zt-ls"><b>例3</b></span> 已知<math display="0"> |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例3</b></span> 已知<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>,且<i>x</i>∈[-π,π],求<i>x</i>的值. |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(48)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 因为<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>></mo> |
| | | <mn>0</mn> |
| | | </math>,所以<i>x</i>是第一或第四象限角. |
| | | </p> |
| | | <p> |
| | | 满足<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>的锐角是<math display="0"> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math>,所以符合条件的第一象限角是<math display="0"> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | 因为<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <div v-if="isShowAnswer48" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 因为<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>></mo> |
| | | <mn>0</mn> |
| | | </math>,所以<i>x</i>是第一或第四象限角. |
| | | </p> |
| | | <p> |
| | | 满足<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>的锐角是<math display="0"> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math>,所以符合条件的第一象限角是<math display="0"> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | 因为<math display="0"> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>, |
| | | </p> |
| | | <p> |
| | | 所以符合条件的第四象限角是<math display="0"> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | <mo>=</mo> |
| | | <mi>cos</mi> |
| | | <mo data-mjx-texclass="NONE"></mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mn>1</mn> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | </math>, |
| | | </p> |
| | | <p> |
| | | 所以符合条件的第四象限角是<math display="0"> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | 所以<math display="0"> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math>或<math display="0"> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | </math>. |
| | | </p> |
| | | <p> |
| | | 所以<math display="0"> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math>或<math display="0"> |
| | | <mi>x</mi> |
| | | <mo>=</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>3</mn> |
| | | </mfrac> |
| | | </math>. |
| | | </p> |
| | | </div> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | |
| | | <p> |
| | | 根据已知特殊的三角函数值求角的方法,借助计算工具,可以解决已知任意三角函数值求角的问题. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>例1</b></span> 已知<math display="0"> |
| | | <mi>α</mi> |
| | | <mo>∈</mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">[</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>,</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">]</mo> |
| | | </mrow> |
| | | </math>,求<i>α</i>的值.(结果精确到0.000 1) |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例1</b></span> 已知<math display="0"> |
| | | <mi>α</mi> |
| | | <mo>∈</mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">[</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>,</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">]</mo> |
| | | </mrow> |
| | | </math>,求<i>α</i>的值.(结果精确到0.000 1) |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(49)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 因为<math display="0"> |
| | | <mi>α</mi> |
| | | <mo>∈</mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">[</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>,</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">]</mo> |
| | | </mrow> |
| | | </math>,所以<i>α</i>在<i>y</i>=sin <i>α</i>的一个单调区间内,这时使sin |
| | | <i>α</i>=0.943 7的角<i>α</i>的值是唯一的. |
| | | <calculator /> |
| | | <div v-if="isShowAnswer49" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 因为<math display="0"> |
| | | <mi>α</mi> |
| | | <mo>∈</mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">[</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>,</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">]</mo> |
| | | </mrow> |
| | | </math>,所以<i>α</i>在<i>y</i>=sin <i>α</i>的一个单调区间内,这时使sin |
| | | <i>α</i>=0.943 7的角<i>α</i>的值是唯一的. |
| | | </p> |
| | | <p> |
| | | 先将科学计算器的精确度设置为0.000 |
| | | 1,再将科学计算器设置为弧度计算模式,然后依次按键: |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0214-4.jpg" /> |
| | | </p> |
| | | <p>结果显示:</p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0214-5.jpg" /> |
| | | </p> |
| | | <p>所以 <i>α</i>≈1.233 6.</p> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例2</b></span> 已知cos <i>α</i>=0.694 |
| | | 3,0°≤<i>α</i>≤180°,求<i>α</i>的值.(结果精确到0.000 1) |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(50)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p> |
| | | 先将科学计算器的精确度设置为0.000 |
| | | 1,再将科学计算器设置为弧度计算模式,然后依次按键: |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0214-4.jpg" /> |
| | | </p> |
| | | <p>结果显示:</p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0214-5.jpg" /> |
| | | </p> |
| | | <p>所以 <i>α</i>≈1.233 6.</p> |
| | | <p> |
| | | <span class="zt-ls"><b>例2</b></span> 已知cos <i>α</i>=0.694 |
| | | 3,0°≤<i>α</i>≤180°,求<i>α</i>的值.(结果精确到0.000 1) |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 因为0°≤<i>α</i>≤180°,所以<i>α</i>在<i>y</i>=cos |
| | | <i>α</i>的一个单调区间内,这时使cos <i>α</i>=0.694 |
| | | 3的角<i>α</i>的值是唯一的. |
| | | </p> |
| | | <div v-if="isShowAnswer50" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 因为0°≤<i>α</i>≤180°,所以<i>α</i>在<i>y</i>=cos |
| | | <i>α</i>的一个单调区间内,这时使cos <i>α</i>=0.694 |
| | | 3的角<i>α</i>的值是唯一的. |
| | | </p> |
| | | <p> |
| | | 先将科学计算器的精确度设置为0.000 |
| | | 1,再将科学计算器设置为角度计算模式,然后依次按键: |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0215-1.jpg" /> |
| | | </p> |
| | | <p>结果显示:</p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0215-2.jpg" /> |
| | | </p> |
| | | <p>所以<i>α</i>≈46.028 5°.</p> |
| | | <p> |
| | | 注意:应当区分所给条件中角的单位是角度还是弧度.如果是角度,计算时应用角度计算模式; |
| | | 如果是弧度,计算时应用弧度计算模式. |
| | | </p> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | |
| | | <li>数学.基础模块</li> |
| | | <li>上册</li> |
| | | </ul> |
| | | |
| | | <div class="padding-116"> |
| | | <p> |
| | | 先将科学计算器的精确度设置为0.000 |
| | | 1,再将科学计算器设置为角度计算模式,然后依次按键: |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例3</b></span> 已知tan <i>α</i>=-2.747 0,<math display="0"> |
| | | <mi>α</mi> |
| | | <mo>∈</mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>,</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>,求<i>α</i>的值.(结果精确到0.000 1) |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(51)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0215-1.jpg" /> |
| | | <calculator /> |
| | | <div v-if="isShowAnswer51" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 因为<math display="0"> |
| | | <mi>α</mi> |
| | | <mo>∈</mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>,</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>,所以<i>α</i>在<i>y</i>=tan <i>α</i>的一个单调区间内,这时使tan |
| | | <i>α</i>=-2.747 0的角<i>α</i>的值是唯一的. |
| | | </p> |
| | | <p> |
| | | 先将科学计算器的精确度设置为0.000 |
| | | 1,再将科学计算器设置为弧度计算模式,然后依次按键: |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0215-5.jpg" /> |
| | | </p> |
| | | <p>结果显示:</p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0215-6.jpg" /> |
| | | </p> |
| | | <p>所以 <i>α</i>≈-1.221 7.</p> |
| | | </div> |
| | | <p class="p-btn" > |
| | | <span> |
| | | <span class="zt-ls"><b>例4</b></span> 已知sin <i>α</i>=-0.857 |
| | | 2,<i>α</i>∈[0,2π],求<i>α</i>的值.(结果精确到0.000 1) |
| | | </span> |
| | | <span class="btn-box" @click="hadleAnswer(52)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.501" height="16.501" viewBox="0 0 20.501 20.501"> |
| | | <path class="a" |
| | | d="M3344.717-15308.5H3337.4a10.186,10.186,0,0,1-7.25-3,10.185,10.185,0,0,1-3-7.25A10.262,10.262,0,0,1,3337.4-15329a10.26,10.26,0,0,1,10.249,10.248,10.129,10.129,0,0,1-2.2,6.341v3.177A.734.734,0,0,1,3344.717-15308.5Zm-9.606-7.29h4.493l.527,1.419c.071.182.156.386.254.608a2.428,2.428,0,0,0,.273.512.986.986,0,0,0,.315.262.971.971,0,0,0,.454.1,1.05,1.05,0,0,0,.773-.327,1.025,1.025,0,0,0,.319-.723,3.3,3.3,0,0,0-.277-1.051l-.062-.161-2.889-7.313c-.119-.321-.228-.607-.335-.873a2.972,2.972,0,0,0-.323-.616,1.56,1.56,0,0,0-.5-.469,1.552,1.552,0,0,0-.781-.181,1.535,1.535,0,0,0-.773.181,1.475,1.475,0,0,0-.5.477,3.674,3.674,0,0,0-.362.739l-.239.627-.054.135-2.824,7.355c-.095.229-.179.46-.25.688a1.529,1.529,0,0,0-.073.477.978.978,0,0,0,.323.72,1.039,1.039,0,0,0,.746.315.838.838,0,0,0,.716-.3,4.676,4.676,0,0,0,.466-.985l.062-.165.527-1.449Zm3.747-1.5h-3.293l1.812-5.124,1.481,5.123Z" |
| | | transform="translate(-3327.144 15329)" /> |
| | | </svg> |
| | | </span> |
| | | <span class="btn-box" @click="openDialog(thinkOne)"> |
| | | <svg xmlns="http://www.w3.org/2000/svg" width="16.545" height="18.112" viewBox="0 0 20.545 22.112"> |
| | | <path class="a" |
| | | d="M3771.2-14311.889a2.356,2.356,0,0,1-1.727-.626c-.027-.054-.053-.1-.079-.148l0-.007c-.123-.224-.2-.371-.076-.629a.869.869,0,0,1,.784-.471.205.205,0,0,1,.158.079.205.205,0,0,0,.158.079.187.187,0,0,0,.038.1.143.143,0,0,0,.117.05h.158a.573.573,0,0,0,.471.158,2.2,2.2,0,0,0,.916-.3l.023-.011a.572.572,0,0,1,.471-.158.575.575,0,0,1,.626.626.526.526,0,0,1,.036.409.664.664,0,0,1-.349.375A3.582,3.582,0,0,1,3771.2-14311.889Zm-1.885-1.723h-.155a.718.718,0,0,1-.784-.63.38.38,0,0,1-.021-.3.976.976,0,0,1,.492-.485l4.86-1.252a1.047,1.047,0,0,1,.784.626c.151.3-.128.61-.471.784l-4.705,1.256Zm-.155-1.885H3769a.716.716,0,0,1-.784-.626c-.149-.3.129-.611.471-.784l4.234-1.1v-.158l-.021.007a7.808,7.808,0,0,1-1.861.31,5.3,5.3,0,0,1-3.137-.942,5.789,5.789,0,0,1-2.666-4.076,6.421,6.421,0,0,1,1.256-5.018,7.038,7.038,0,0,1,2.194-1.568,7.848,7.848,0,0,1,2.666-.472,6.43,6.43,0,0,1,2.979.784,4.958,4.958,0,0,1,2.2,2.194,5.522,5.522,0,0,1,.313,5.177,13.113,13.113,0,0,1-1.256,1.882l-.313.313a2.156,2.156,0,0,0-.78,1.244l0,.012a1.731,1.731,0,0,1-1.727,1.723l-.313.158-3.292.939Zm1.256-6.271v1.256h1.41v-1.256Zm.784-4.234c.718,0,1.1.271,1.1.784a.925.925,0,0,1-.316.783l-.468.156a2.235,2.235,0,0,0-.63.471l-.012.024a2.2,2.2,0,0,0-.3.918v.155h1.1v-.155a1.2,1.2,0,0,1,.313-.629.543.543,0,0,0,.315-.153c.007,0,.315,0,.315-.16a1.226,1.226,0,0,0,.626-.626,2.277,2.277,0,0,0,.313-1.1,1.409,1.409,0,0,0-.626-1.252,2.337,2.337,0,0,0-1.569-.471,2.258,2.258,0,0,0-2.507,2.353l1.252.154A1.121,1.121,0,0,1,3771.2-14326Zm-6.51,9.645a.769.769,0,0,1-.549-.237.772.772,0,0,1-.235-.549.772.772,0,0,1,.235-.548l.939-.939a.781.781,0,0,1,.55-.234.772.772,0,0,1,.547.234.772.772,0,0,1,.238.549.772.772,0,0,1-.238.549l-.939.938A.769.769,0,0,1,3764.686-14316.356Zm13.174-.157a.774.774,0,0,1-.549-.234l-.943-.942a.678.678,0,0,1-.233-.47.678.678,0,0,1,.233-.47.774.774,0,0,1,.549-.234.774.774,0,0,1,.549.234l.942.939a.427.427,0,0,1,.228.324.74.74,0,0,1-.228.618A.774.774,0,0,1,3777.859-14316.514Zm2.9-6.351h-1.414c-.469-.158-.784-.474-.784-.784a.743.743,0,0,1,.784-.784h1.414a.743.743,0,0,1,.784.784A.743.743,0,0,1,3780.761-14322.864Zm-17.566-.158h-1.41c-.469-.157-.784-.473-.784-.784a.743.743,0,0,1,.784-.784h1.41a.743.743,0,0,1,.784.784A.743.743,0,0,1,3763.195-14323.022Zm13.861-5.723a.759.759,0,0,1-.529-.237.776.776,0,0,1-.235-.549.772.772,0,0,1,.235-.549l.939-.938a.44.44,0,0,1,.413-.238.759.759,0,0,1,.529.238.772.772,0,0,1,.235.549.772.772,0,0,1-.235.548l-.942.939A.435.435,0,0,1,3777.055-14328.745Zm-11.429,0a.776.776,0,0,1-.55-.237l-.939-1.1a.678.678,0,0,1-.235-.469.678.678,0,0,1,.235-.47.772.772,0,0,1,.549-.238.772.772,0,0,1,.549.238l.939,1.1a.675.675,0,0,1,.238.47.675.675,0,0,1-.238.47A.767.767,0,0,1,3765.626-14328.745Zm5.724-2.273a.743.743,0,0,1-.784-.785v-1.413c.157-.469.473-.784.784-.784a.743.743,0,0,1,.784.784v1.413A.743.743,0,0,1,3771.35-14331.019Z" |
| | | transform="translate(-3761 14334.001)" /> |
| | | </svg> |
| | | </span> |
| | | </p> |
| | | <p>结果显示:</p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0215-2.jpg" /> |
| | | </p> |
| | | <p>所以<i>α</i>≈46.028 5°.</p> |
| | | <p> |
| | | 注意:应当区分所给条件中角的单位是角度还是弧度.如果是角度,计算时应用角度计算模式; |
| | | 如果是弧度,计算时应用弧度计算模式. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>例3</b></span> 已知tan <i>α</i>=-2.747 0,<math display="0"> |
| | | <mi>α</mi> |
| | | <mo>∈</mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>,</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>,求<i>α</i>的值.(结果精确到0.000 1) |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> 因为<math display="0"> |
| | | <mi>α</mi> |
| | | <mo>∈</mo> |
| | | <mrow data-mjx-texclass="INNER"> |
| | | <mo data-mjx-texclass="OPEN">(</mo> |
| | | <mo>−</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo>,</mo> |
| | | <mfrac> |
| | | <mi>π</mi> |
| | | <mn>2</mn> |
| | | </mfrac> |
| | | <mo data-mjx-texclass="CLOSE">)</mo> |
| | | </mrow> |
| | | </math>,所以<i>α</i>在<i>y</i>=tan <i>α</i>的一个单调区间内,这时使tan |
| | | <i>α</i>=-2.747 0的角<i>α</i>的值是唯一的. |
| | | </p> |
| | | <p> |
| | | 先将科学计算器的精确度设置为0.000 |
| | | 1,再将科学计算器设置为弧度计算模式,然后依次按键: |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0215-5.jpg" /> |
| | | </p> |
| | | <p>结果显示:</p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0215-6.jpg" /> |
| | | </p> |
| | | <p>所以 <i>α</i>≈-1.221 7.</p> |
| | | <p> |
| | | <span class="zt-ls"><b>例4</b></span> 已知sin <i>α</i>=-0.857 |
| | | 2,<i>α</i>∈[0,2π],求<i>α</i>的值.(结果精确到0.000 1) |
| | | </p> |
| | | <p class="block"> |
| | | <span class="zt-ls2"><b>分析</b></span> 因为sin <i>α</i>=-0.857 |
| | | 2<0,在[0,2π]范围内有两个<i>α</i>值满足条件,它们分别位于第三象限和第四象限,即<i>α</i>在[π,2π]范围内.可用科学计算器先求出sin |
| | | <i>α</i>=0.857 2所对应的锐角,再利用诱导公式求出所求的角. |
| | | </p> |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | 先将科学计算器的精确度设置为0.000 |
| | | 1,再将科学计算器设置为弧度计算模式,然后依次按键: |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0215-7.jpg" /> |
| | | </p> |
| | | <p>结果显示:</p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0215-8.jpg" /> |
| | | </p> |
| | | <div v-if="isShowAnswer52" > |
| | | <p> |
| | | <span class="zt-ls"><b>解</b></span> |
| | | 先将科学计算器的精确度设置为0.000 |
| | | 1,再将科学计算器设置为弧度计算模式,然后依次按键: |
| | | </p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0215-7.jpg" /> |
| | | </p> |
| | | <p>结果显示:</p> |
| | | <p class="center"> |
| | | <img class="img-c" alt="" src="../../assets/images/0215-8.jpg" /> |
| | | </p> |
| | | <p>即</p> |
| | | <p class="center">sin 1.029 8≈0.857 2.</p> |
| | | <p>因为</p> |
| | | <p class="center">sin(π+1.029 8)=-sin 1.029 8≈-0.857 2,</p> |
| | | <p>所以符合条件的第三象限角是π+1.029 8≈4.171 4.</p> |
| | | <p>因为</p> |
| | | <p class="center">sin(2π-1.029 8)=-sin 1.029 8≈-0.857 2,</p> |
| | | <p>所以符合条件的第四象限角是2π-1.029 8≈5.253 4.</p> |
| | | <p> |
| | | 所以满足sin <i>α</i>=-0.857 |
| | | 2,<i>α</i>∈[0,2π]的角<i>α</i>的集合为{4.171 4,5.253 4}. |
| | | </p> |
| | | </div> |
| | | </div> |
| | | </div> |
| | | </div> |
| | |
| | | </li> |
| | | </ul> |
| | | <div class="padding-116"> |
| | | <p>即</p> |
| | | <p class="center">sin 1.029 8≈0.857 2.</p> |
| | | <p>因为</p> |
| | | <p class="center">sin(π+1.029 8)=-sin 1.029 8≈-0.857 2,</p> |
| | | <p>所以符合条件的第三象限角是π+1.029 8≈4.171 4.</p> |
| | | <p>因为</p> |
| | | <p class="center">sin(2π-1.029 8)=-sin 1.029 8≈-0.857 2,</p> |
| | | <p>所以符合条件的第四象限角是2π-1.029 8≈5.253 4.</p> |
| | | <p> |
| | | 所以满足sin <i>α</i>=-0.857 |
| | | 2,<i>α</i>∈[0,2π]的角<i>α</i>的集合为{4.171 4,5.253 4}. |
| | | </p> |
| | | <p class="left"> |
| | | <img class="img-gn" alt="" src="../../assets/images/stlx.jpg" /> |
| | | </p> |
| | |
| | | </div> |
| | | <!-- 211 --> |
| | | <div class="page-box hidePage" page="218"></div> |
| | | <!-- 解题思路弹窗 --> |
| | | <el-dialog :visible.sync="thinkingDialog" width="40%" :append-to-body="true" :show-close="false" |
| | | @close="closeDialog" class="thinkDialog"> |
| | | <div slot="title" class="think-header" |
| | | style="padding: 0; text-align: center; color: #333;display:flex;justify-content: center;"> |
| | | <span style=""> 分析 </span> |
| | | <svg style="position: absolute; right:10px;cursor: pointer;" @click="thinkingDialog = false" t="1718596022986" |
| | | class="icon" viewBox="0 0 1024 1024" version="1.1" xmlns="http://www.w3.org/2000/svg" p-id="4252" width="20" |
| | | height="20" xmlns:xlink="http://www.w3.org/1999/xlink"> |
| | | <path |
| | | d="M176.661601 817.172881C168.472798 825.644055 168.701706 839.149636 177.172881 847.338438 185.644056 855.527241 199.149636 855.298332 207.338438 846.827157L826.005105 206.827157C834.193907 198.355983 833.964998 184.850403 825.493824 176.661601 817.02265 168.472798 803.517069 168.701706 795.328267 177.172881L176.661601 817.172881Z" |
| | | fill="#979797" p-id="4253"></path> |
| | | <path |
| | | d="M795.328267 846.827157C803.517069 855.298332 817.02265 855.527241 825.493824 847.338438 833.964998 839.149636 834.193907 825.644055 826.005105 817.172881L207.338438 177.172881C199.149636 168.701706 185.644056 168.472798 177.172881 176.661601 168.701706 184.850403 168.472798 198.355983 176.661601 206.827157L795.328267 846.827157Z" |
| | | fill="#979797" p-id="4254"></path> |
| | | </svg> |
| | | </div> |
| | | <ul> |
| | | <li v-for="(item, index) in thinkData" :key="index"> |
| | | <div v-if="index <= showIndex" style="display: flex"> |
| | | <span style="position: relative"> |
| | | <span style="position: absolute; top: 16px; left: 13px; color: #fff">{{ index + 1 }}</span> |
| | | <img src="../../assets/images/icon/blue-group.png" alt="" style="margin-right: 10px" |
| | | v-if="index < thinkOne.length - 1" /> |
| | | <img src="../../assets/images/icon/blue.png" alt="" v-if="index == thinkOne.length - 1" |
| | | style="margin-right: 10px" /> |
| | | </span> |
| | | <p class="txt-p" v-html="item"></p> |
| | | </div> |
| | | </li> |
| | | </ul> |
| | | <div @click="changeNext" style=" |
| | | display: flex; |
| | | flex-direction: column; |
| | | align-items: center; |
| | | justify-content: center; |
| | | "> |
| | | <img src="../../assets/images/icon/mouse.png" alt="" v-if="showIndex < thinkData.length - 1" /> |
| | | <svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" t="1710234570135" |
| | | class="icon" viewBox="0 0 1024 1024" version="1.1" p-id="5067" width="15" height="15"> |
| | | <path |
| | | d="M2.257993 493.371555 415.470783 906.584344 512 1003.113561 608.529217 906.584344 1021.742007 493.371555 925.212789 396.842337 512 810.055127 98.787211 396.842337Z" |
| | | fill="#1296db" p-id="5068" /> |
| | | <path |
| | | d="M2.257993 117.980154 415.470783 531.192944 512 627.722161 608.529217 531.192944 1021.742007 117.980154 925.212789 21.450937 512 434.663727 98.787211 21.450937Z" |
| | | fill="#1296db" p-id="5069" /> |
| | | </svg> |
| | | </div> |
| | | </el-dialog> |
| | | </div> |
| | | </template> |
| | | |
| | |
| | | import paint from '@/components/paint/index.vue' |
| | | import examinations from "@/components/examinations/index.vue"; |
| | | import fillInTable from "@/components/fillInTable/index.vue"; |
| | | import calculator from '@/components/calculator/index.vue' |
| | | const handleShow = (num) => { |
| | | const obj = {} |
| | | for (let index = 0; index < num; index++) { |
| | | obj['isShowAnswer' + index] = false |
| | | } |
| | | return obj |
| | | } |
| | | const showObj = handleShow(60) |
| | | export default { |
| | | name: "", |
| | | props: { |
| | |
| | | type: Object, |
| | | }, |
| | | }, |
| | | components: { examinations, fillInTable,paint }, |
| | | components: { examinations, fillInTable,paint,calculator }, |
| | | data() { |
| | | return { |
| | | ...showObj, |
| | | isShowAnswer:false, |
| | | queryDataOne: { |
| | | stemTxt:"完成下表,并利用“五点法”画出<i>y</i>=3sin <i>x</i>在区间[0,2π]内的简图,并说明<i>y</i>=3sin <i>x</i>的图像与正弦函数<i>y</i>=sin <i>x</i>的图像的区别和联系.", |
| | |
| | | ["y=1-cosx", "", "", "", "", ""], |
| | | ], |
| | | answer:"<p>1,0,-1,0,1</p><p>0,1,2,1,0</p>" |
| | | } |
| | | |
| | | }, |
| | | showIndex:0, |
| | | thinkingDialog: false, |
| | | thinkData:[], |
| | | thinkOne:[ |
| | | '因为sin <i>α</i>=-0.8572<0,在[0,2π]范围内有两个<i>α</i>值满足条件,它们分别位于第三象限和第四象限,即<i>α</i>在[π,2π]范围内.可用科学计算器先求出sin<i>α</i>=0.857 2所对应的锐角,再利用诱导公式求出所求的角.' |
| | | ] |
| | | } |
| | | }, |
| | | methods:{ |
| | | hadleAnswer(index) { |
| | | this['isShowAnswer' + index] = !this['isShowAnswer' + index] |
| | | }, |
| | | openDialog(queryData) { |
| | | this.thinkData = queryData |
| | | this.thinkingDialog = !this.thinkingDialog |
| | | }, |
| | | closeDialog() { |
| | | this.showIndex = 0 |
| | | }, |
| | | changeNext() { |
| | | if (this.showIndex < this.thinkData.length - 1) this.showIndex = this.showIndex + 1 |
| | | } |
| | | } |
| | | } |
| | | </script> |
| | | |
| | |
| | | border: 1px solid #00adee; |
| | | display: flex; |
| | | } |
| | | li { |
| | | list-style: none; |
| | | } |
| | | </style> |