6.=ax2+2ax+4,若x1<x2,x1+x2=1-a,则( ) A.f(x1)<f(x2) B.f(x1)=f(x2) C.f(x1)>f(x2) D.f(x1)与f(x2)的大小不能确定 解析:函数f(x)=ax2+2ax+4(0<a<3).二次函数的图象开口向上.对称轴为.0<a<3.∴ x1+x2=1-a∈.x1与x2的中点在(-1.)之间.x1<x2.∴ x2到对称轴的距离大于x1到对称轴的距离.∴ f(x1)<f(x2) .选A. 【
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题目列表(包括答案和解析)
(陕西卷理5)已知函数f(x)=
若f(f(0))=4a,则实数a等于( )
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(陕西卷理5)已知函数f(x)=
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131101230448911530655/SYS201311012304489115306004_ST/0.png)
若f(f(0))=4a,则实数a等于( )
A.
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131101230448911530655/SYS201311012304489115306004_ST/1.png)
B.
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131101230448911530655/SYS201311012304489115306004_ST/2.png)
C.2
D.9
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(陕西卷理5)已知函数f(x)=
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131103173157826803406/SYS201311031731578268034007_ST/0.png)
若f(f(0))=4a,则实数a等于( )
A.
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131103173157826803406/SYS201311031731578268034007_ST/1.png)
B.
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131103173157826803406/SYS201311031731578268034007_ST/2.png)
C.2
D.9
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(陕西卷理5)已知函数f(x)=
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131103102337047010723/SYS201311031023370470107003_ST/0.png)
若f(f(0))=4a,则实数a等于( )
A.
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131103102337047010723/SYS201311031023370470107003_ST/1.png)
B.
![](http://thumb.zyjl.cn/pic6/res/gzsx/web/STSource/20131103102337047010723/SYS201311031023370470107003_ST/2.png)
C.2
D.9
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(陕西卷理5)已知函数f(x)=
若f(f(0))=4a,则实数a等于( )
查看答案和解析>>