题目
题型:不详难度:来源:
已知函数f(x)=" cos(" 2x+
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042936-13156.png)
(Ⅰ)求函数f(x)的最小正周期和值域;
(Ⅱ)在△ABC中,角A、B、C的对边分别为a、b、c,满足
2
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042936-79127.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042937-44282.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042937-64248.png)
答案
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042937-86413.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042937-32354.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042937-28199.png)
解析
试题分析:(Ⅰ)因为
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042938-68687.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042938-10411.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042938-12902.png)
所以,最小正周期
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042937-86413.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042937-32354.png)
(Ⅱ)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042938-80606.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042939-38391.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042939-41988.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042939-95363.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042939-72630.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042940-75559.png)
又,
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042940-75080.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042939-41988.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042940-38513.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042940-47445.png)
而
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042940-95465.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042941-58084.png)
由正弦定理,有
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042941-15723.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042941-49714.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042941-13216.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042941-21063.png)
点评:典型题,综合考查了三角函数的图象和性质,三角恒等变换,正弦定理的应用,能较好地考查学生的计算能力。
核心考点
试题【(本小题满分12分)已知函数f(x)=" cos(" 2x+)+sin2x.(Ⅰ)求函数f(x)的最小正周期和值域;(Ⅱ)在△ABC中,角A、B、C的对边分别为】;主要考察你对解三角形应用等知识点的理解。[详细]
举一反三
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042929-82037.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042930-90205.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042930-20162.png)
A.![]() | B.![]() | C.![]() | D.![]() |
已知
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042922-46086.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042923-32113.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042923-91589.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042923-68966.png)
(1) 求
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042923-92602.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042923-29685.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042914-82888.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042914-38343.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042914-34916.png)
A.![]() | B.![]() | C.![]() | D.![]() |
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042906-98039.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042906-17584.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042906-82899.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042906-76469.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042906-54943.png)
(1)求
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042906-98039.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042907-70501.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042907-31597.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042902-69890.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042902-61620.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042902-63148.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042903-67934.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020042902-69890.png)
A.![]() | B.![]() | C.![]() | D.![]() |
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