题目内容
已知函数
满足满足
;
(1)求
的解析式及单调区间;
(2)若
,求
的最大值。
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/20120704131112809803.png)
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/201207041311128393102.png)
(1)求
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/20120704131112870803.png)
(2)若
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/201207041311128942180.png)
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/201207041311129231039.png)
解:(1)
令
得:
得:
在
上单调递增
得:
的解析式为
且单调递增区间为
,单调递减区间为
;
(2)
得
①当
时,
在
上单调递增
时,
与
矛盾
②当
时,
得:当
时,
,
令
;则
当
时,
当
时,
的最大值为
。
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/201207041311129495163.png)
令
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/20120704131112999539.png)
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/201207041311130881005.png)
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/201207041311131344697.png)
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/201207041311131613755.png)
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/201207041311131872195.png)
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/20120704131113214752.png)
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/201207041311132423413.png)
得:
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/20120704131113266803.png)
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/201207041311132992021.png)
且单调递增区间为
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/201207041311133241001.png)
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/20120704131113358966.png)
(2)
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/201207041311133844158.png)
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/201207041311134151629.png)
①当
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/20120704131113440882.png)
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/201207041311134711975.png)
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/20120704131113500752.png)
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/20120704131113529766.png)
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/201207041311135611199.png)
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/201207041311135861117.png)
②当
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/20120704131113617859.png)
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/201207041311136423869.png)
得:当
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/201207041311136751278.png)
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/201207041311136993224.png)
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/201207041311137343505.png)
令
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/201207041311137592079.png)
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/201207041311137901849.png)
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/201207041311138163353.png)
当
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/20120704131113849856.png)
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/201207041311138741635.png)
当
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/201207041311139001650.png)
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/201207041311139301039.png)
![](http://thumb.zyjl.cn/pic1/upload/papers/g02/20120704/20120704131113955593.png)
![](http://thumb.zyjl.cn/images/loading.gif)
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