满分5 >
高中数学试题 >
已知各项为正的等比数列{an}中,a4与a14的等比中项为,则2a7+a11的最...
已知各项为正的等比数列{a
n}中,a
4与a
14的等比中项为
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102729743341123/SYS201311031027297433411004_ST/0.png)
,则2a
7+a
11的最小值为( )
A.16
B.8
C.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102729743341123/SYS201311031027297433411004_ST/1.png)
D.4
考点分析:
相关试题推荐
如图,水平放置的三棱柱ABC-A
1B
1C
1中,侧棱AA
1⊥平面A
1B
1C
1,其正视图是边长为a的正方形.俯视图是边长为a的正三角形,则该三棱柱的侧视图的面积为( )
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102729743341123/SYS201311031027297433411003_ST/images0.png)
A.a
2B.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102729743341123/SYS201311031027297433411003_ST/0.png)
a
2C.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102729743341123/SYS201311031027297433411003_ST/1.png)
a
2D.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102729743341123/SYS201311031027297433411003_ST/2.png)
a
2
查看答案
函数f(x)=(x+1)lnx的零点有( )
A.0个
B.1个
C.2个
D.3个
查看答案
平面向量
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102729743341123/SYS201311031027297433411001_ST/0.png)
、
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102729743341123/SYS201311031027297433411001_ST/1.png)
的夹角为60°,
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102729743341123/SYS201311031027297433411001_ST/2.png)
=(2,0),|
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102729743341123/SYS201311031027297433411001_ST/3.png)
|=1,则|
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102729743341123/SYS201311031027297433411001_ST/4.png)
+
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102729743341123/SYS201311031027297433411001_ST/5.png)
|=( )
A.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102729743341123/SYS201311031027297433411001_ST/6.png)
B.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102729743341123/SYS201311031027297433411001_ST/7.png)
C.3
D.7
查看答案
设全集U=R,A={x|x(x+3)<0},B={x|x<-1},则图中阴影部分表示集合( )
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102729743341123/SYS201311031027297433411000_ST/images0.png)
A.{x|-3<x<-1}
B.{x|-3<x<0}
C.{x|x>0}
D.{x|x<-1}
查看答案
设函数f(x)=a
x-(k-1)a
-x(a>0且a≠1)是定义域为R的奇函数.
(1)求k值;
(2)若f(1)<0,试判断函数单调性并求使不等式f(x
2+tx)+f(4-x)<0恒成立的t的取值范围;
(3)若f(1)=
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102729743201999/SYS201311031027297432019020_ST/0.png)
,且g(x)=a
2x+a
-2x-2mf(x)在[1,+∞)上的最小值为-2,求m的值.
查看答案