名校
1 . 下列说法中错误的是__________ (填序号).
①命题“
,有
”的否定是“
,有
”;
②若一个命题的逆命题为真命题,则它的否命题也一定为真命题;
③已知
,若
为真命题,则实数
的取值范围是
;
④“
”是“
”成立的充分条件.
①命题“
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/281b260fe94c42258b7fa8c6bc6cefa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b27d88a4295635c2d6d00e1aa29efc47.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/727483dc6109a1e22b9a8855a5719380.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5eeff91263ef999174b55518dc95d0ea.png)
②若一个命题的逆命题为真命题,则它的否命题也一定为真命题;
③已知
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4ab9bdbc4c514ee6ce2c4559cf8de207.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eca91737a79d662f6869baf93a071862.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a44e22b80c4d775cea5f632123f0d9f3.png)
④“
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb0469b312798e19c24fe494d03fb0a9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5915d59c5ab0ba013b8cf43c854c284b.png)
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