解题方法
1 . 对于函数
,给出四个判断:
①若
对一切实数
成立,则
的取值范围是
;
②若
的值域是
,则
的取值范围是
;
③若
对一切实数
成立,则
的取值范围是
;
④若
的值域是
,则
的取值范围是
.
其中正确判断的序号是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8540bab5c4326a5752dce1cc9eb39956.png)
①若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/256f3981024e53f373a80aad40e994ae.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d27e0400d730672ae2110ff48786dd1d.png)
②若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fe7d5809da02c15a43a0e9a898b9086.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7dcdd87d593df4a5c5e98d47fe1cfa6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d27e0400d730672ae2110ff48786dd1d.png)
③若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/256f3981024e53f373a80aad40e994ae.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ff7e39b335e3b5250b7f727e16a4a03.png)
④若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fe7d5809da02c15a43a0e9a898b9086.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7dcdd87d593df4a5c5e98d47fe1cfa6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ff7e39b335e3b5250b7f727e16a4a03.png)
其中正确判断的序号是( )
A.①② | B.③④ | C.②③ | D.①④ |
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