题目内容
已知函数
,
.
(Ⅰ)已知
,若
,求
的值;
(Ⅱ)设
,当
时,求
在
上的最小值;
(Ⅲ)求函数
在区间
上的最大值.
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941501630.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941501632.png)
(Ⅰ)已知
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941517534.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941532652.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941548536.png)
(Ⅱ)设
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408240259415791278.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941595475.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941610473.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941626523.png)
(Ⅲ)求函数
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941642754.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941657401.png)
(Ⅰ)
;(Ⅱ)当
时,
最小值为
;(Ⅲ)当
时,
在
上的最大值为0;当
时,
在
上的最大值为
;当
时,
在
上的最大值为
.
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941688606.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941704455.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941610473.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941735385.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941751434.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941766481.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941657401.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941798514.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941766481.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941657401.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941844423.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941860418.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941766481.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941657401.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941922454.png)
试题分析:(Ⅰ)将函数
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941938447.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941532652.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941969479.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941985759.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025942000653.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025942016604.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941532652.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941688606.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941610473.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941610473.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941766481.png)
试题解析:(Ⅰ)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408240259421251310.png)
由
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941938447.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941985759.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941532652.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025942188573.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941688606.png)
(Ⅱ)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025942219421.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408240259422341200.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408240259422661033.png)
当
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025942281369.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025942297616.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025942312673.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025942375529.png)
当
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025942390455.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025942297616.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025942422667.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025942437595.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408240259424532002.png)
当
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941704455.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941610473.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941735385.png)
(本问也可直接利用图像说明理由求解) 6分
(Ⅲ)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025942546838.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408240259425621473.png)
①记
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408240259425781020.png)
当
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025942593588.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025942609443.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025942640954.png)
当
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025942656588.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941751434.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025942702836.png)
②记
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025942718996.png)
当
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025942734538.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025942749442.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025942765952.png)
当
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025942780581.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025942812499.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408240259428271187.png)
当
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025942843521.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025942858448.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025942874850.png)
③记
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408240259428901050.png)
当
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025942905598.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025942609443.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408240259429521010.png)
当
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025942968590.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941751434.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025942999942.png)
由上讨论可知:
当
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941751434.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408240259430301090.png)
当
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025943046540.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408240259430771229.png)
当
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025943092520.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408240259431081625.png)
当
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025943124523.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408240259431391660.png)
当
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025942749442.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408240259431701321.png)
综上所述:当
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941751434.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941766481.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941657401.png)
当
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941798514.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941766481.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941657401.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941844423.png)
当
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941860418.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941766481.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941657401.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824025941922454.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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