题目内容
已知
,
,且
//
.设函数
.
(Ⅰ)求函数
的解析式.
(Ⅱ)若在锐角
中,
,边
,求
周长的最大值.
![](http://thumb.1010pic.com/pic2/upload/papers/20140823/20140823183354035825.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140823/20140823183354050431.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140823/20140823183354066204.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140823/20140823183354097203.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140823/20140823183354113424.gif)
(Ⅰ)求函数
![](http://thumb.1010pic.com/pic2/upload/papers/20140823/20140823183354113424.gif)
(Ⅱ)若在锐角
![](http://thumb.1010pic.com/pic2/upload/papers/20140823/20140823183354144400.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140823/20140823183354191559.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140823/20140823183354206324.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140823/20140823183354144400.gif)
由条件得
,
2分
4分
由
得
6分
得
7分
由余弦定理
13分
所以 周长
16分
![](http://thumb.1010pic.com/pic2/upload/papers/20140823/20140823183354253748.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140823/2014082318335426971.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140823/20140823183354284589.gif)
由
![](http://thumb.1010pic.com/pic2/upload/papers/20140823/20140823183354191559.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140823/20140823183354315504.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140823/20140823183354331540.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140823/20140823183354503390.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140823/2014082318335451872.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140823/201408231833545341569.gif)
所以 周长
![](http://thumb.1010pic.com/pic2/upload/papers/20140823/20140823183354549568.gif)
略
![](http://thumb2018.1010pic.com/images/loading.gif)
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