【题文】已知集合,,若,则实数的取值范围是
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答案
【答案】
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323062559-54589.png)
解析
【解析】解:因为集合
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323062557-62586.png)
,
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323062558-17603.png)
,若
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323062558-15612.png)
,则利用结合包含关系,需要考虑集合B为空集和B不为空集两种情况得到结论为
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323062559-54589.png)
,注意边界点的验证。
举一反三
【题文】已知集合
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323062535-29908.png)
,则
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323062535-29577.png)
( )
【题文】已知集合
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323062432-18953.png)
,则
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323062433-57623.png)
( )
【题文】已知全集
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323062408-44895.png)
,集合
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323062408-98775.png)
,
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323062408-31020.png)
,则
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323062408-75846.png)
为( )
A. {1,2,4} | B. {2,3,4} | C. {0,2,4} | D. {0,2,3,4} |
【题文】已知全集
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323062322-32193.png)
,集合
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323062322-92025.png)
,
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323062323-75611.png)
,则
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323062323-22141.png)
为( )
A. {1,2,4} | B. {2,3,4} | C. {0,2,4} | D. {0,2,3,4} |
【题文】已知
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323062312-95635.png)
,则
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323062312-52795.png)
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