2012·湖南·一模
1 . 已知函数
,若f(x)
恒成立,则a的取值范围是____
![](https://img.xkw.com/dksih/QBM/2012/2/27/1570778392223744/1570778397343744/STEM/130bbf2ebf7e4dd69f4c967af7b3ed22.png?resizew=159)
![](https://img.xkw.com/dksih/QBM/2012/2/27/1570778392223744/1570778397343744/STEM/b2a5a1d5717b49dcad297cc01bde1770.png?resizew=60)
您最近一年使用:0次
11-12高三上·广东深圳·阶段练习
2 . 设函数
.
(Ⅰ)若存在
,使得
,求实数
的取值范围;
(Ⅱ)若
是(Ⅰ)中的最大值,且正数
,
满足
,证明:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb95a868233f61ec2ff8cb84d5be077c.png)
(Ⅰ)若存在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/799b324b514d6044672c133d8fef2dc4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0ce5118394e703092a3ac1deb901eeeb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
(Ⅱ)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab04de6651256f6281e9f4c1dc3c7955.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/deba97f507ced9a7884d4d5c855f4e3a.png)
您最近一年使用:0次
10-11高三·广东惠州·阶段练习
3 . 已知数列
、
满足
,
,数列
的前
项和为
.
(1)求数列
的通项公式;
(2)设
,求证:
;
(3)求证:对任意的
有
成立.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be5a84371c8f5c6155980d18acc68a14.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/128d43fbfe37d2334f8666239efc7e32.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
(1)求数列
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/034ba25825c13725931c483aa47c9363.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cc8bb07c3ef0cf84181557b568ebfbd9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/13711c968ad3c0df0bbd73eeee30ce24.png)
(3)求证:对任意的
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36b98ef143f8159f3a7dafa1fd2f2370.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed5a1c2d90fb2d436610f670051f3b86.png)
您最近一年使用:0次