【题文】
【题文】
题型:难度:来源:
【题文】
![](http://img.shitiku.com.cn/uploads/allimg/20200325/20200325103546-46045.png)
答案
【答案】B
解析
【解析】 由(x
1-2)(x
2-2)<0得
![](http://img.shitiku.com.cn/uploads/allimg/20200325/20200325103547-95882.png)
或
![](http://img.shitiku.com.cn/uploads/allimg/20200325/20200325103547-30476.png)
,
不妨令
![](http://img.shitiku.com.cn/uploads/allimg/20200325/20200325103547-95882.png)
,又由x
1+x
2<4,得
![](http://img.shitiku.com.cn/uploads/allimg/20200325/20200325103547-35469.png)
,
![](http://img.shitiku.com.cn/uploads/allimg/20200325/20200325103548-73592.png)
又因为x>2时,f(x)递增,所以
![](http://img.shitiku.com.cn/uploads/allimg/20200325/20200325103548-13320.png)
所以
![](http://img.shitiku.com.cn/uploads/allimg/20200325/20200325103548-81415.png)
由
![](http://img.shitiku.com.cn/uploads/allimg/20200325/20200325103548-64841.png)
, 得
![](http://img.shitiku.com.cn/uploads/allimg/20200325/20200325103549-80486.png)
,即
![](http://img.shitiku.com.cn/uploads/allimg/20200325/20200325103549-73979.png)
所以
![](http://img.shitiku.com.cn/uploads/allimg/20200325/20200325103549-77327.png)
![](http://img.shitiku.com.cn/uploads/allimg/20200325/20200325103549-84713.png)
举一反三
【题文】设奇函数
![](http://img.shitiku.com.cn/uploads/allimg/20200325/20200325103516-97894.png)
在
![](http://img.shitiku.com.cn/uploads/allimg/20200325/20200325103516-45218.png)
上是增函数,且
![](http://img.shitiku.com.cn/uploads/allimg/20200325/20200325103516-67333.png)
,则不等式
![](http://img.shitiku.com.cn/uploads/allimg/20200325/20200325103516-26320.png)
的解集为
【题文】设奇函数
![](http://img.shitiku.com.cn/uploads/allimg/20200325/20200325103425-67302.png)
在
![](http://img.shitiku.com.cn/uploads/allimg/20200325/20200325103426-66681.png)
上是增函数,且
![](http://img.shitiku.com.cn/uploads/allimg/20200325/20200325103426-12336.png)
,则不等式
![](http://img.shitiku.com.cn/uploads/allimg/20200325/20200325103426-54112.png)
的解集为
【题文】函数
![](http://img.shitiku.com.cn/uploads/allimg/20200325/20200325103409-84574.png)
是定义在R上恒不为0的函数,对任意
![](http://img.shitiku.com.cn/uploads/allimg/20200325/20200325103409-41270.png)
都有
![](http://img.shitiku.com.cn/uploads/allimg/20200325/20200325103409-45464.png)
,若
![](http://img.shitiku.com.cn/uploads/allimg/20200325/20200325103409-44906.png)
,则数列
![](http://img.shitiku.com.cn/uploads/allimg/20200325/20200325103409-34607.png)
的前n项和S
n的取值范围是 ( )
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