【题文】已知集合=( )A.B.C.D.
题型:难度:来源:
【题文】已知集合
![](http://img.shitiku.com.cn/uploads/allimg/20200314/20200314042759-68513.png)
=( )
答案
【答案】A.
解析
【解析】
试题分析:由
![](http://img.shitiku.com.cn/uploads/allimg/20200314/20200314042800-33294.png)
.所以
![](http://img.shitiku.com.cn/uploads/allimg/20200314/20200314042801-36047.png)
或
![](http://img.shitiku.com.cn/uploads/allimg/20200314/20200314042801-93843.png)
.所以
![](http://img.shitiku.com.cn/uploads/allimg/20200314/20200314042801-65866.png)
=
![](http://img.shitiku.com.cn/uploads/allimg/20200314/20200314042801-44812.png)
.本题的解题关键是集合A里的元素是x的值,这也是本题易错点.
考点:1.集合的描述法的表示.2.补集的概念.
举一反三
【题文】若集合
![](http://img.shitiku.com.cn/uploads/allimg/20200314/20200314042742-49706.png)
,则满足条件
![](http://img.shitiku.com.cn/uploads/allimg/20200314/20200314042742-44525.png)
有
个.
【题文】设集合A是实数集R的子集,如果点
![](http://img.shitiku.com.cn/uploads/allimg/20200314/20200314042609-56651.png)
满足:对任意
![](http://img.shitiku.com.cn/uploads/allimg/20200314/20200314042609-71818.png)
,都存在
![](http://img.shitiku.com.cn/uploads/allimg/20200314/20200314042610-19033.png)
使得
![](http://img.shitiku.com.cn/uploads/allimg/20200314/20200314042610-34316.png)
,则称
![](http://img.shitiku.com.cn/uploads/allimg/20200314/20200314042610-21068.png)
为集合A的聚点.用Z表示整数集,则在下列集合中,以0为聚点的集合有( )
(1)
![](http://img.shitiku.com.cn/uploads/allimg/20200314/20200314042611-64701.png)
(2)不含0的实数集R
(3)
![](http://img.shitiku.com.cn/uploads/allimg/20200314/20200314042611-25657.png)
(4)整数集Z
A.(1)(3) | B.(1)(4) | C.(2)(3) | D.(1)(2)(4) |
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