【题文】已知 (1)当时,求;(2) 若,求实数的取值范围.
【题文】已知 (1)当时,求;(2) 若,求实数的取值范围.
题型:难度:来源:
【题文】已知
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115748-36003.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115748-66038.gif)
(1)当
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115748-46096.gif)
时,求
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115749-74188.gif)
;
(2) 若
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115749-31609.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115749-92151.gif)
,求实数
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115749-78235.gif)
的取值范围.
答案
【答案】解: (1)
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115749-24439.gif)
,
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115749-69345.gif)
………2分
(2)
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115749-90066.gif)
或
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115750-37552.gif)
…………………………………1分
当
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115750-52771.gif)
时,即
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115750-70004.gif)
得
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115750-33195.gif)
满足
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115749-31609.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115749-92151.gif)
………1分
当
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115750-72070.gif)
时使
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115749-31609.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115749-92151.gif)
即
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115750-57688.gif)
或
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115751-14692.gif)
………2分
解得:
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115751-11788.gif)
……………………………………………………1分
综上所述,
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115749-78235.gif)
的取值范围是
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115751-60901.gif)
解析
【解析】略
举一反三
【题文】已知
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115740-39839.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115740-79049.gif)
(1)当
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115740-57980.gif)
时,求
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115740-26846.gif)
;
(2) 若
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115740-64424.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115741-78162.gif)
,求实数
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115741-48301.gif)
的取值范围.
【题文】记集合M
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115730-26212.png)
,N
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115730-10254.png)
,则
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115730-59096.png)
( )
A.
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115730-61305.png)
B.
C.
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115731-23747.png)
D.
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115731-10267.png)
【题文】记集合M
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115725-23990.png)
,N
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115726-72978.png)
,则
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115726-46828.png)
( )
A.
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115726-94837.png)
B.
C.
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115726-14882.png)
D.
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115727-27320.png)
【题文】已知集合
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115706-87793.png)
,则
![](http://img.shitiku.com.cn/uploads/allimg/20200323/20200323115706-80858.png)
( )
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