在
中,
(1)若
的值;
(2)若
,
,试比较
与
大小,说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/882589c896c6993d9687f0e14a283481.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08b6aee6891eebfd1fb8d4efa8f91d69.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b49bd51260d0ffdaf5e1e00fd090e8a9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/889d615211411983123ccbb07a191aac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c9a45589b1a59c94a33744279941c90b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/596e24bef4f7b3092833f78458ddfaa1.png)
17-18九年级下·全国·单元测试 查看更多[4]
人教版九年级下册数学_第28章_锐角三角函数_单元检测试卷(已下线)专题28.2+锐角三角函数(基础篇)(专项练习)-2021-2022学年九年级数学下册基础知识专项讲练(人教版)(已下线)第10讲 锐角三角函数(4大考点)-2022-2023学年九年级数学考试满分全攻略(浙教版)第34章 锐角三角函数 单元测试卷 人教 版(五四制)九年级下册数学
更新时间:2018-11-26 13:29:16
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【知识点】 互余两角三角函数的关系解读
相似题推荐
解答题-计算题
|
较易
(0.85)
名校
【推荐1】如果已知两个角的正弦值和余弦值,我们可以利用和的正弦公式来求已知两角的正弦值,其公式为:sin(
+
)= sin
cos
+ cos
sin
,请利用这个公式,解决下列问题:
(1)计算sin75°的值;
(2)利用公式证明:sin2
=2 sin
cos
;并在已知sin
=
的条件下,求sin2
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b5858ee1ce52b251816757257a11c29.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b5858ee1ce52b251816757257a11c29.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b5858ee1ce52b251816757257a11c29.png)
(1)计算sin75°的值;
(2)利用公式证明:sin2
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c24095e409b025db711f14be783a406c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c24095e409b025db711f14be783a406c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c24095e409b025db711f14be783a406c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c24095e409b025db711f14be783a406c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eac97e6740365c85ad857aff85cefbe5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c24095e409b025db711f14be783a406c.png)
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解答题-证明题
|
较易
(0.85)
【推荐2】嘉嘉在某次作业中得到如下结果:
,
,
,
,
.
据此,嘉嘉猜想:对于任意锐角
,
,若
,均有
.
(1)当
,
时,验证
是否成立?
(2)嘉嘉的猜想是否成立?若成立,请结合如图所示
给予证明,其中
所对的边为
,
所对的边为
,斜边为
;若不成立,请举出一个反例;
![](https://img.xkw.com/dksih/QBM/2023/5/21/3242295547379712/3242733374545920/STEM/5806261ecddc4fc4bd3291b9c36a01cc.png?resizew=153)
(3)利用上面的证明方法,直接写出
与
,
之间的关系.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ff57272d9659b494d7eef8fbcdc4fb25.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d1a2d43ff0527846c6ccabaa18a244f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acf3fd20b7bc5e52a33a6d2290322ed7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/69bb7556c9c61d606ec2d87aedfd8d2c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4187ff8a7c578b0611657d80af3a4aff.png)
据此,嘉嘉猜想:对于任意锐角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b5858ee1ce52b251816757257a11c29.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bcaf5cff829cbe4bea35089b25fa0cc1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1d18c6b8b542b58c92ef1ff2bbcbd29b.png)
(1)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6c96cb3ac8290e09c55d4eb336a8608.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b235c077d324c45527cee213a48c1fee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1d18c6b8b542b58c92ef1ff2bbcbd29b.png)
(2)嘉嘉的猜想是否成立?若成立,请结合如图所示
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd967903ed5a6f640a5b801ec8be0070.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3818a2c9919d358b4c3713396093822b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/febc9a89d0d1c97b88c0f4acd32b4e67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/071a7e733d466949ac935b4b8ee8d183.png)
![](https://img.xkw.com/dksih/QBM/2023/5/21/3242295547379712/3242733374545920/STEM/5806261ecddc4fc4bd3291b9c36a01cc.png?resizew=153)
(3)利用上面的证明方法,直接写出
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6cc9750c313ee972124cb62c4a6fb7ea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0b4179e1ab8705cf19ea7aaf48888843.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4d66c03d4ca06819a6ce7fc8ea6de0f0.png)
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