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若等差数列{an}的前5项和S5=25,且a2=3,则a7=( ) A.12 B...
若等差数列{an}的前5项和S5=25,且a2=3,则a7=( )
A.12
B.13
C.14
D.15
考点分析:
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已知
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102429882116581/SYS201311031024298821165007_ST/0.png)
,函数y=f(x+φ)的图象关于直线x=0对称,则φ的值可以是( )
A.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102429882116581/SYS201311031024298821165007_ST/1.png)
B.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102429882116581/SYS201311031024298821165007_ST/2.png)
C.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102429882116581/SYS201311031024298821165007_ST/3.png)
D.
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下列函数中,周期为π,且在
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102429882116581/SYS201311031024298821165006_ST/0.png)
上为减函数的是( )
A.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102429882116581/SYS201311031024298821165006_ST/1.png)
B.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102429882116581/SYS201311031024298821165006_ST/2.png)
C.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102429882116581/SYS201311031024298821165006_ST/3.png)
D.
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设f(x)=3
x-x
2,则在下列区间中,使函数f(x)有零点的区间是( )
A.[0,1]
B.[1,2]
C.[-2,-1]
D.[-1,0]
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已知等比数列{a
n}满足a
1+a
2=3,a
2+a
3=6,则a
7=( )
A.64
B.81
C.128
D.243
查看答案
已知|
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102429882116581/SYS201311031024298821165003_ST/0.png)
|=2,|
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102429882116581/SYS201311031024298821165003_ST/1.png)
|=3,向量
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102429882116581/SYS201311031024298821165003_ST/2.png)
与
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102429882116581/SYS201311031024298821165003_ST/3.png)
的夹角为150°,则
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102429882116581/SYS201311031024298821165003_ST/4.png)
与
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102429882116581/SYS201311031024298821165003_ST/5.png)
方向的投影为( )
A.-
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102429882116581/SYS201311031024298821165003_ST/6.png)
B.-1
C.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102429882116581/SYS201311031024298821165003_ST/7.png)
D.
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