二次函数
图像如图,对称轴为直线
,则下列叙述正确的是( )
![](https://img.xkw.com/dksih/QBM/2019/8/14/2268501046919168/2273731575332865/STEM/c27df61f86e14b8d966f69422fd09875.png?resizew=140)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fe6337d68cd5653767e3a1889b8b2e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/99c6875d552e9fff3c7d655f3a59b166.png)
![](https://img.xkw.com/dksih/QBM/2019/8/14/2268501046919168/2273731575332865/STEM/c27df61f86e14b8d966f69422fd09875.png?resizew=140)
A.ac>0 | B.b2<4ac | C.b=2a | D.a+b+c>0 |
更新时间:2019-08-25 09:25:43
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【推荐1】在平面直角坐标系
中,点
,
在抛物线
(
)上,设抛物线的对称轴为直线
.若
,则
的取值范围是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7795aec93c2c7ac2fd93e6747ca6516c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b5bac94908f9f24ef1618a72cece5cba.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/87a11362ec4cce9314a4558365ca4404.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a90385c676848de67293e3ed6bc000fe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/94440d3e4c073f94f2b266ff99d50e74.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a6f7b16d65f1b2b8bea8cf4a83fde925.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/461d5ca1dd31b64600857d8f2ba792a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36a1b09c653185842513e24ebba60bb3.png)
A.![]() | B.![]() | C.![]() | D.![]() |
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【推荐2】小明为了研究关于
的方程
的根的个数问题,先将该等式转化为
,再分别画出函数
的图象与函数
的图象(如图),当方程有且只有四个根时,
的取值范围是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d1fbaaa1a5178381b11754958e62762.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a3d7168bcc94dee3cc6a887a8dfa711.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/344ccbf79da6ad7e3709d6fa72efb756.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fb2827563fb3943cf4e57d2977291d2f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0a532e15e232cb4b99a8d4d07c89575.png)
A.![]() | B.![]() | C.![]() | D.![]() |
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【推荐1】抛物线y=ax2+bx+c(a,b,c为常数)的对称轴为x=﹣2,过点(1,﹣2)和点(x0,y0),且c>0.有下列结论:①a<0;②对任意实数m都有:am2+bm≥4a﹣2b;③16a+c>4b;④若
>﹣4,则
>c.其中正确结论的个数为( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79b752f0f189e5d8666daea73e145dff.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8112f9185c7d48b015d9cd0525616b31.png)
A.1个 | B.2个 | C.3个 | D.4个 |
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【推荐2】二次函数
的图象如图所示,有如下结论:①
;②
;③
;④
(m为实数).其中正确结论的个数是( )
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/6/8638b230-bb10-4307-acf4-ec4b3aade88d.png?resizew=266)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a90385c676848de67293e3ed6bc000fe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73c21bd0bd90a89b7ff5ac0eacf612a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa285de4d015f208441ffe9a84bbd780.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ba65efa1f701570eb2c5d06b2bfabf7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4f9457ea96205b652a136dbd422b3142.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/11/6/8638b230-bb10-4307-acf4-ec4b3aade88d.png?resizew=266)
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