题目
题型:解答题难度:简单来源:不详
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075534-82979.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075535-43166.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075535-43166.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075535-93442.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075535-30177.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075535-30177.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075536-16684.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075536-91405.png)
(1)求cos(
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075535-43166.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075535-30177.png)
(2)若0<
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075535-43166.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075536-89528.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075536-89528.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075535-30177.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075535-30177.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075536-76835.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075535-43166.png)
答案
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075536-21607.png)
(2)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075537-81797.png)
解析
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075537-16887.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075536-16684.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075536-91405.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075535-43166.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075535-30177.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075535-43166.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075536-89528.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075536-89528.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075535-30177.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075535-30177.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075536-76835.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075537-76351.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075537-29790.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075538-65027.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075535-43166.png)
解:(Ⅰ)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075538-51309.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075538-90345.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075538-14491.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075538-69799.png)
即
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075538-95530.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075539-81645.png)
(Ⅱ)∵
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075539-36408.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075539-36399.png)
∵
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075536-21607.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075537-76351.png)
∵
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075539-30238.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075537-29790.png)
∴
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075539-21117.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075540-90936.png)
核心考点
试题【(本小题9分)已知向量 =(cos,sin),=(cos,sin),||=.(1)求cos(-)的值;(2)若0<<,-<<0,且sin=-,求sin的值.】;主要考察你对弧度制等知识点的理解。[详细]
举一反三
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075532-57931.png)
A.![]() | B.![]() | C.2 | D.![]() |
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075529-46235.png)
A.![]() | B.![]() | C.![]() | D.![]() |
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075526-25168.png)
A.![]() | B.![]() |
C.![]() | D.![]() |
A.![]() | B.![]() | C.![]() | D.![]() |
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075523-26300.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075523-11577.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190821/20190821075523-26300.png)
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