解题方法
1 . 如图,在直角坐标系中,设单位圆O与x轴的非负半轴相交于点
,以x轴的非负半轴为始边分别作任意角
,
,它们的终边分别与单位圆相交于点
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/13/a11c83f7-4a15-43e3-9fda-c5c7e25e104a.png?resizew=185)
(1)请在图中作出以x轴的非负半轴为始边时角
的终边
(与单位圆交于点P),并说明AP与
的长度关系;
(2)根据第(1)问的发现,证明两角差的余弦公式;
(3)由两角差的余弦公式推导两角差的正弦公式.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c8950c7bc835103d52ceffab14b6b31a.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/2708fa6298e52f617383efc175b71ddc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a18722354086c42e62334983fc50eb6a.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/13/a11c83f7-4a15-43e3-9fda-c5c7e25e104a.png?resizew=185)
(1)请在图中作出以x轴的非负半轴为始边时角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fd927b4b5a7875528c1b54aa4bb8b2dd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/abd13974aebe38eb2a1d744a01ea5aa5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4ae97d7f57b159b72a23eb909b74d7c3.png)
(2)根据第(1)问的发现,证明两角差的余弦公式;
(3)由两角差的余弦公式推导两角差的正弦公式.
您最近一年使用:0次
20-21高一·江苏·课后作业
解题方法
2 . 求证:
,
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/370cd955f4d1f8d1a829425eaa64e6c9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f34a4cf3e88ba292fec8aaf926979801.png)
您最近一年使用:0次
2021-10-30更新
|
188次组卷
|
3卷引用:7.2 三角函数概念