题目
题型:难度:来源:
【题文】已知函数
满足
,且
,当
时( )
![](http://img.shitiku.com.cn/uploads/allimg/20200327/20200327100727-39948.png)
![](http://img.shitiku.com.cn/uploads/allimg/20200327/20200327100727-70509.png)
![](http://img.shitiku.com.cn/uploads/allimg/20200327/20200327100728-81456.png)
![](http://img.shitiku.com.cn/uploads/allimg/20200327/20200327100728-43903.png)
A.![]() | B.![]() | C.![]() | D.以上皆不对. |
答案
【答案】B
解析
【解析】本题考查二次函数的单调性和对称性,指数函数的性质.
因为函数
满足
,所以二次函数
图像的对称轴是
,即
又
二次函数为
在
上是减函数,在
上是增函数;指数函数
是增函数;(1)当
时,
,所以
(2)当
时,
,所以
;综上:![](http://img.shitiku.com.cn/uploads/allimg/20200327/20200327100732-32966.png)
.故选B
因为函数
![](http://img.shitiku.com.cn/uploads/allimg/20200327/20200327100727-39948.png)
![](http://img.shitiku.com.cn/uploads/allimg/20200327/20200327100727-70509.png)
![](http://img.shitiku.com.cn/uploads/allimg/20200327/20200327100727-39948.png)
![](http://img.shitiku.com.cn/uploads/allimg/20200327/20200327100729-76187.png)
![](http://img.shitiku.com.cn/uploads/allimg/20200327/20200327100729-53160.png)
![](http://img.shitiku.com.cn/uploads/allimg/20200327/20200327100729-96896.png)
![](http://img.shitiku.com.cn/uploads/allimg/20200327/20200327100730-25912.png)
![](http://img.shitiku.com.cn/uploads/allimg/20200327/20200327100730-10594.png)
![](http://img.shitiku.com.cn/uploads/allimg/20200327/20200327100730-33903.png)
![](http://img.shitiku.com.cn/uploads/allimg/20200327/20200327100730-99063.png)
![](http://img.shitiku.com.cn/uploads/allimg/20200327/20200327100731-70814.png)
![](http://img.shitiku.com.cn/uploads/allimg/20200327/20200327100731-58731.png)
![](http://img.shitiku.com.cn/uploads/allimg/20200327/20200327100731-19277.png)
![](http://img.shitiku.com.cn/uploads/allimg/20200327/20200327100731-77166.png)
![](http://img.shitiku.com.cn/uploads/allimg/20200327/20200327100732-92954.png)
![](http://img.shitiku.com.cn/uploads/allimg/20200327/20200327100732-47735.png)
![](http://img.shitiku.com.cn/uploads/allimg/20200327/20200327100732-32966.png)
.故选B
核心考点
试题【【题文】已知函数满足,且,当时( )A.B.C.D.以上皆不对.】;主要考察你对一次函数的图象和性质等知识点的理解。[详细]
举一反三
【题文】已知函数
,且
的解集为(-2,1)则函数
的图象为( )
![](http://img.shitiku.com.cn/uploads/allimg/20200327/20200327100650-57851.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200327/20200327100650-69012.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200327/20200327100651-33811.gif)