题目
题型:不详难度:来源:
若a、b、c是△ABC三个内角A、B、C所对边,且
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042415-51427.png)
(1)求
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042415-26421.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042415-51606.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042415-38506.png)
答案
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042415-97098.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042415-62854.png)
解析
试题分析:由正弦定理得
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042415-26754.png)
即
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042416-98662.png)
故
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042416-61567.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042415-97098.png)
(2)由余弦定理
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042416-79058.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042416-23166.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042416-20174.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042416-17490.png)
∴
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042416-95953.png)
点评:解三角形的内容包括正弦定理、余弦定理以及三角形的面积公式,对这方面的考查经常出现,有时结合三角函数进行考查,以中等难度题目为主,同学们一定抓好基础知识.
核心考点
举一反三
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042405-80869.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042405-44547.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042405-48450.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042406-42601.png)
已知
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042356-33601.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042356-20636.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042357-61566.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042357-17460.png)
(Ⅰ)求角
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042357-72774.png)
(Ⅱ)求函数
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042357-56569.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042348-72302.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042348-49211.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042349-91034.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042349-24506.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042349-67034.png)
①求f(x)图象对称中心坐标
②若△ABC三边a、b、c满足b2=ac,且b边所对角为x,求x的范围及f(x)值域。
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042343-39288.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042343-45775.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042343-71337.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042343-51968.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042343-23551.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042344-38106.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042344-38546.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042344-15577.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042344-46006.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042343-45775.png)
已知
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042336-17682.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042337-82754.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042337-61009.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042337-13472.png)
(Ⅰ)求角
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042337-62801.png)
(Ⅱ)若
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042337-64091.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042338-79550.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042338-72993.png)
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