题目内容
20.已知
(m为常数,且m>0)有极大值
,
(Ⅱ)求曲线
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132342282421.gif)
(1)1(2)
或![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132342328521.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132342297499.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132342328521.gif)
((Ⅰ)![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132342344636.gif)
则
,
由列表得:
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132342578415.gif)
,∴
.
(Ⅱ)由(Ⅰ)知
,则![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132342672591.gif)
∴
或
由
,
.
所以切线方程为:
即
;
或
即
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132342344636.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132342360630.gif)
则
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132342375246.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132342391436.gif)
由列表得:
x | ![]() | -m | ![]() | ![]() | ![]() |
![]() | + | 0 | - | 0 | + |
![]() | ![]() | 极大值 | ![]() | 极小值 | ![]() |
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132342578415.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132342594694.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132342609247.gif)
(Ⅱ)由(Ⅰ)知
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132342640680.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132342672591.gif)
∴
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132342687227.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132342703297.gif)
由
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132342718386.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132342796584.gif)
所以切线方程为:
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132342890566.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132342297499.gif)
或
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132342921656.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132342328521.gif)
![](http://thumb.zyjl.cn/images/loading.gif)
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