题目
题型:不详难度:来源:
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019153148-52862.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019153148-28540.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019153148-68062.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019153149-89295.png)
则
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019153149-29096.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019153149-32115.png)
答案
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019153149-25276.png)
解析
(1)直接利用条件
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019153149-89295.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019153149-87424.png)
(2)由于
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019153150-81533.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019153150-84775.png)
解:(1)由余弦定理得
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019153150-59060.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019153150-62171.png)
(2)因为
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019153150-81533.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019153150-84775.png)
由正弦定理得
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019153151-23529.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019153151-10478.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019153149-25276.png)
核心考点
举一反三
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019153100-95947.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019153101-86097.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019153101-49855.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019153101-49855.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019153101-80283.png)
(Ⅰ)求
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019153101-58806.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019153102-35502.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019153102-16388.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019153037-14997.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019153037-72131.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019152843-81384.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019152843-46470.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019152843-57137.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019152843-40567.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019152844-34499.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019152844-22487.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019152822-27501.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019152822-50247.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019152822-72638.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019152822-27501.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191019/20191019152757-13510.png)
A.4 | B.2 | C.1 | D.不确定 |
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