【题文】已知,,,则实数的取值范围是_________________.
【题文】已知,,,则实数的取值范围是_________________.
题型:难度:来源:
【题文】已知
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322134725-50979.png)
,
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322134726-18186.png)
,
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322134726-66747.png)
,则实数
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322134727-10668.png)
的取值范围是
_________________.
答案
【答案】
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322134727-19735.png)
解析
【解析】
试题分析:因为
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322134726-66747.png)
,(1)当
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322134727-84301.png)
时,则
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322134727-75099.png)
,即
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322134728-63751.png)
;(2)当
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322134728-65115.png)
时,则
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322134729-44535.png)
,解得
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322134729-82614.png)
,综合(1)(2)得
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322134727-19735.png)
.
考点:集合之间的包含关系.
举一反三
【题文】已知全集
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322134638-65548.png)
,集合
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322134638-14388.png)
,
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322134638-57263.png)
则
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322134639-21088.png)
等于__________.
【题文】(本小题满分12分)
已知
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322134524-92032.png)
,
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322134525-98564.png)
.
(Ⅰ)若
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322134525-84028.png)
,求实数a的取值范围;
(Ⅱ)若
![](http://img.shitiku.com.cn/uploads/allimg/20200322/20200322134526-48498.png)
,求实数a的取值范围.
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