题目
题型:解答题难度:一般来源:不详
![](http://img.shitiku.com.cn/uploads/allimg/20190824/20190824004133-82918.png)
(Ⅰ) 求
![](http://img.shitiku.com.cn/uploads/allimg/20190824/20190824004134-49623.png)
(Ⅱ) 当
![](http://img.shitiku.com.cn/uploads/allimg/20190824/20190824004134-72618.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190824/20190824004135-40785.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190824/20190824004135-83359.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190824/20190824004135-72526.png)
答案
![](http://img.shitiku.com.cn/uploads/allimg/20190824/20190824004135-51016.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190824/20190824004135-54478.png)
解析
![](http://img.shitiku.com.cn/uploads/allimg/20190824/20190824004136-57755.png)
然后将cosA的值代入即可.
(2)根据面积公式由cosA,先求出sinA,然后再利用
![](http://img.shitiku.com.cn/uploads/allimg/20190824/20190824004136-65146.png)
解:(1)
![](http://img.shitiku.com.cn/uploads/allimg/20190824/20190824004134-49623.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190824/20190824004136-85116.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190824/20190824004136-42382.png)
(2)
![](http://img.shitiku.com.cn/uploads/allimg/20190824/20190824004136-86300.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190824/20190824004137-43740.png)
则
![](http://img.shitiku.com.cn/uploads/allimg/20190824/20190824004137-56661.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190824/20190824004135-54478.png)
核心考点
试题【 在△ABC中,角A,B,C所对的边分别为a,b,c,且. (Ⅰ) 求的值;(Ⅱ) 当,的面积时,求的值.】;主要考察你对同角三角函数的基本关系等知识点的理解。[详细]
举一反三
![](http://img.shitiku.com.cn/uploads/allimg/20190824/20190824004106-72177.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190824/20190824004106-97343.png)
A.![]() | B.![]() | C.![]() | D.![]() |
![](http://img.shitiku.com.cn/uploads/allimg/20190824/20190824004016-37219.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190824/20190824003951-80396.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190824/20190824003951-91148.png)
A.![]() | B.-![]() | C.![]() | D.-![]() |
![](http://img.shitiku.com.cn/uploads/allimg/20190824/20190824003838-33046.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190824/20190824003839-57039.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190824/20190824003839-30257.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190824/20190824003840-89399.png)
A.![]() | B.![]() |
C.![]() | D.![]() |
![](http://img.shitiku.com.cn/uploads/allimg/20190824/20190824003822-70868.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190824/20190824003822-64141.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190824/20190824003822-13151.png)
![](http://img.shitiku.com.cn/uploads/allimg/20190824/20190824003822-17916.png)
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