【题文】集合=( )A.B.C.D.
题型:难度:来源:
【题文】集合
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322230239-76064.png)
=( )
答案
【答案】B
解析
【解析】
试题分析:因为,
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322230240-44909.png)
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322230241-35705.png)
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322230241-22517.png)
=
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322230239-15137.png)
,故选B。
考点:函数的概念,集合的运算。
点评:简单题,为进行集合的运算,需要首先确定集合中的元素。注意借助于数轴处理。
举一反三
【题文】若集合M={3、4、5、6、7、8},N={x
2-5x+4≤0}则
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322230027-41571.png)
( )
A. {3}![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322230028-69856.png) | B. {3、4} | C. {3<x≤5}![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322230028-69856.png) | D. {3、4、5} |
【题文】已知集合A={x|y=
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322225951-57215.png)
,x∈R},B="{y|" y=x
2+1,x∈R},则A∩B为( )
A. {1} B.[0,+∞) C
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322225952-51960.png)
.
【题文】设全集是实数集R,
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322225943-29065.png)
,B=
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322225944-28947.png)
(1)当a=4时,求A∩B和A∪B;
(2)若
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322225944-83304.png)
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322225944-13711.png)
,求实数
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322225945-40070.png)
的取值范围.
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