【题文】设,则的值为( )A.0B.1C.2D.3
题型:难度:来源:
【题文】设
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324190637-96418.png)
,则
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324190637-92448.png)
的值为( )
答案
【答案】C
解析
【解析】本题考查分段函数的含义.
求分段函数的函数值,把自变量代入到对应的某一段的解析式中即求出函数值.
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324190637-19708.png)
则
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324190637-70245.png)
即
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324190637-29733.png)
故选C
举一反三
【题文】设集合
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324190537-63822.png)
,
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324190537-61858.png)
,给出如下四个图形,其中能表
示从集合
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324190538-25214.png)
到集合
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324190538-78352.png)
的函数关系的是 ( )
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324190539-17127.png)
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324190539-26092.png)
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324190540-52066.png)
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324190540-89026.png)
(A) (B) (C) (D)
【题文】已知函数
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324190533-25313.png)
,则
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324190534-63304.png)
( )
A.4 | B.![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324190534-68922.png) | C.-4 | D.-![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324190534-68922.png) |
【题文】已知集合A=R,B=R
+,f:A→B是从A到B的一个映射,若f:x→2x-1,则B中的
元素3的原象为 ( )
【题文】设f(x)=|x-1|-|x|,则f[f(
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324190501-27553.png)
)]= ( )
A.-![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324190501-27553.png) | B.0 | C.![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324190501-27553.png) | D.1 |
【题文】若函数f(x) =
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324190453-35746.png)
+ 2
x + log
2x的值域是 {3,
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324190453-61746.png)
-1, 5 +
![](http://img.shitiku.com.cn/uploads/allimg/20200324/20200324190454-89514.png)
, 20},
则其定义域是 ( )
A.{0,1,2,4} | B.{ ,1,2,4} | C.{ ,2,4} | D.{ ,1,2,4,8} |
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