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在等差数列{an}中,已知a4+a8=16,则a2+a10=( ) A.12 B...
在等差数列{an}中,已知a4+a8=16,则a2+a10=( )
A.12
B.16
C.20
D.24
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下列命题中正确的是( )
A.若命题p为真命题,命题q为假命题,则命题“p∧q”为真命题
B.命题“若xy=0,则x=0”的否命题为:“若xy=0,则x≠0”
C.“
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”是“
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”的充分不必要条件
D.命题“∀x∈R,2
x>0”的否定是“
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”
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已知函数
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102640454206051/SYS201311031026404542060002_ST/0.png)
,若f[f(0)]=4a,则实数a的值为( )
A.
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B.
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C.2
D.9
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复数
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102640454206051/SYS201311031026404542060001_ST/0.png)
(i是虚数单位)的虚部是( )
A.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102640454206051/SYS201311031026404542060001_ST/1.png)
B.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102640454206051/SYS201311031026404542060001_ST/2.png)
C.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102640454206051/SYS201311031026404542060001_ST/3.png)
D.
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函数
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102640454206051/SYS201311031026404542060000_ST/0.png)
的定义域为( )
A.[-2,0)∪(0,2]
B.(-1,0)∪(0,2]
C.[-2,2]
D.(-1,2]
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设数列{a
n}的前n项和记为S
n且
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102640454061060/SYS201311031026404540610020_ST/0.png)
设数列{b
n}的前n项和为
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102640454061060/SYS201311031026404540610020_ST/1.png)
(1)求a
n;
(2)求T
n;
(3)设函数f(x)=-x
2+4x,是否存在实数λ使得当x≤λ时,
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131103102640454061060/SYS201311031026404540610020_ST/2.png)
对任意n∈N
*恒成立,若存在,求出λ的取值范围,若不存在,说明理由.
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