【题文】满足条件∪{1}={1,2,3}的集合的个数是( )A.B.C.D.
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【题文】满足条件
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322154959-87031.png)
∪{1}={1,2,3}的集合
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322154959-87031.png)
的个数是( )
答案
【答案】B
解析
【解析】满足条件的M中必须含有{2,3},但最多只能有{1,2,3}
举一反三
【题文】对于函数
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322154914-56635.png)
,若
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322154914-56635.png)
=x,则称x为
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322154914-56635.png)
的“不动点”;若
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322154914-52211.png)
,则称x为
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322154914-56635.png)
“稳定点”,函数
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322154914-56635.png)
的“不动点”和“稳定点”的集合分别记为A和B,既
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322154914-20005.png)
.
(1)证明:A
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322154915-25619.png)
B
(2)若
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322154915-89733.png)
,且
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322154916-21446.png)
,求实数a的取值范围.
【题文】已知集合
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322154850-40721.png)
,则下列式子表示正确的有( )
①
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322154850-64928.png)
②
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322154850-84453.png)
③
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322154850-80743.png)
④
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322154851-66103.png)
【题文】集合U,M,N,P如图所示,则图中阴影部分所表示的集合是( )
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322154836-40049.png)
【题文】集合A={x∈N|
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322154826-61069.png)
∈N}用列举法表示为
.
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