满分5 >
高中数学试题 >
已知{an}是等差数列,a1=1,公差d≠0,Sn为其前n项和,若a1,a2,a...
已知{an}是等差数列,a1=1,公差d≠0,Sn为其前n项和,若a1,a2,a5成等比数列,则S8= .
考点分析:
相关试题推荐
已知复数z=
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124323822111466/SYS201310251243238221114010_ST/0.png)
(i是虚数单位),则|z|=
.
查看答案
在平面上,
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124323822111466/SYS201310251243238221114009_ST/0.png)
,
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124323822111466/SYS201310251243238221114009_ST/1.png)
=1,
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124323822111466/SYS201310251243238221114009_ST/2.png)
.若|
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124323822111466/SYS201310251243238221114009_ST/3.png)
|<
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124323822111466/SYS201310251243238221114009_ST/4.png)
,则|
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124323822111466/SYS201310251243238221114009_ST/5.png)
|的取值范围是( )
A.(0,
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124323822111466/SYS201310251243238221114009_ST/6.png)
]
B.(
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124323822111466/SYS201310251243238221114009_ST/7.png)
,
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124323822111466/SYS201310251243238221114009_ST/8.png)
]
C.(
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124323822111466/SYS201310251243238221114009_ST/9.png)
,
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124323822111466/SYS201310251243238221114009_ST/10.png)
]
D.(
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124323822111466/SYS201310251243238221114009_ST/11.png)
,
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124323822111466/SYS201310251243238221114009_ST/12.png)
]
查看答案
4cos50°-tan40°=( )
A.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124323822111466/SYS201310251243238221114008_ST/0.png)
B.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124323822111466/SYS201310251243238221114008_ST/1.png)
C.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124323822111466/SYS201310251243238221114008_ST/2.png)
D.2
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124323822111466/SYS201310251243238221114008_ST/3.png)
-1
查看答案
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124323822111466/SYS201310251243238221114007_ST/images0.png)
执行如图所示的程序框图,如果输出S=3,那么判断框内应填入的条件是( )
A.k≤6
B.k≤7
C.k≤8
D.k≤9
查看答案
已知圆C
1:(x-2)
2+(y-3)
2=1,圆C
2:(x-3)
2+(y-4)
2=9,M,N分别是圆C
1,C
2上的动点,P为x轴上的动点,则|PM|+|PN|的最小值为( )
A.5
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124323822111466/SYS201310251243238221114006_ST/0.png)
-4
B.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124323822111466/SYS201310251243238221114006_ST/1.png)
1
C.6-2
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131025124323822111466/SYS201310251243238221114006_ST/2.png)
D.
查看答案