题目内容
(本小题满分10分)
在
中,
,
。
(Ⅰ)求
的值;
(Ⅱ)设
的面积
,求
的长。
在
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823134119308309.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823134119339399.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823134119355358.gif)
(Ⅰ)求
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823134119371264.gif)
(Ⅱ)设
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823134119308309.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823134119402504.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823134119417241.gif)
(Ⅰ)![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823134119433531.gif)
(Ⅱ)![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823134119449358.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823134119433531.gif)
(Ⅱ)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823134119449358.gif)
(Ⅰ)由
,得
,
由
,得
。
所以
。·································· 5分
(Ⅱ)由
得
,
由(Ⅰ)知
,
故
,·················································································· 8分
又
,
故
,
。
所以
。 10分
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823134119339399.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823134119480511.gif)
由
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823134119355358.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823134119511474.gif)
所以
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408231341195271176.gif)
(Ⅱ)由
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823134119402504.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823134119573733.gif)
由(Ⅰ)知
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823134119433531.gif)
故
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823134119683383.gif)
又
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823134119745851.gif)
故
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823134119839570.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823134119854459.gif)
所以
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823134119901763.gif)
![](http://thumb.zyjl.cn/images/loading.gif)
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