满分5 >
高中数学试题 >
等比数列{an}的前n项和为Sn,已知S3=a2+10a1,a5=9,则a1=(...
等比数列{a
n}的前n项和为S
n,已知S
3=a
2+10a
1,a
5=9,则a
1=( )
A.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124315745710845/SYS201310251243157457108002_ST/0.png)
B.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124315745710845/SYS201310251243157457108002_ST/1.png)
C.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124315745710845/SYS201310251243157457108002_ST/2.png)
D.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124315745710845/SYS201310251243157457108002_ST/3.png)
考点分析:
相关试题推荐
设复数z满足(1-i)z=2i,则z=( )
A.-1+i
B.-1-i
C.1+i
D.1-i
查看答案
已知集合M={x|(x-1)
2<4,x∈R},N={-1,0,1,2,3},则M∩N=( )
A.{0,1,2}
B.{-1,0,1,2}
C.{-1,0,2,3}
D.{0,1,2,3}
查看答案
设函数
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124315745708655/SYS201310251243157457086020_ST/0.png)
常数且a∈(0,1).
(1)当a=
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124315745708655/SYS201310251243157457086020_ST/1.png)
时,求f(f(
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124315745708655/SYS201310251243157457086020_ST/2.png)
));
(2)若x
满足f(f(x
))=x
,但f(x
)≠x
,则称x
为f(x)的二阶周期点,试确定函数有且仅有两个二阶周期点,并求二阶周期点x
1,x
2;
(3)对于(2)中x
1,x
2,设A(x
1,f(f(x
1))),B(x
2,f(f(x
2))),C(a
2,0),记△ABC的面积为s(a),求s(a)在区间[
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124315745708655/SYS201310251243157457086020_ST/3.png)
,
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124315745708655/SYS201310251243157457086020_ST/4.png)
]上的最大值和最小值.
查看答案
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124315745708655/SYS201310251243157457086019_ST/images0.png)
椭圆C:
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124315745708655/SYS201310251243157457086019_ST/0.png)
=1(a>b>0)的离心率
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124315745708655/SYS201310251243157457086019_ST/1.png)
,a+b=3.
(1)求椭圆C的方程;
(2)如图,A,B,D是椭圆C的顶点,P是椭圆C上除顶点外的任意点,直线DP交x轴于点N直线AD交BP于点M,设BP的斜率为k,MN的斜率为m,证明2m-k为定值.
查看答案
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124315745708655/SYS201310251243157457086018_ST/images0.png)
如图,直四棱柱ABCD-A
1B
1C
1D
1中,AB∥CD,AD⊥AB,AB=2,AD=
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124315745708655/SYS201310251243157457086018_ST/0.png)
,AA
1=3,E为CD上一点,DE=1,EC=3
(1)证明:BE⊥平面BB
1C
1C;
(2)求点B
1到平面EA
1C
1 的距离.
查看答案