1 . 已知关于
的不等式
的解集是
,其中
,则下列结论
①
;
②
;
③
;
④
.
正确的有__________ .(填上所有正确的序号).
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1eaceb060128b297563ec2e51278e191.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f803a468e5d66004e57372a5bf2c5e1b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/26d8dafc71b106f39f4e15442220897b.png)
①
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/39a7ce24c5952d0bcf3217323f7176d3.png)
②
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4668557586f194effd9e806de1f223eb.png)
③
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/35a2bc72538891166ee0a93dbb504b91.png)
④
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7dbc2b1bab43073170d7f6abeb64099b.png)
正确的有
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2 . 如果函数f(x)=x2﹣2bx+2在区间[3,+∞)上是增函数,则b的取值范围为
A.b=3 | B.b≥3 | C.b≤3 | D.b≠3 |
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