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已知{an}为等差数列,其公差为-2,且a7是a3与a9的等比中项,Sn为{an...
已知{an}为等差数列,其公差为-2,且a7是a3与a9的等比中项,Sn为{an}的前n项和,n∈N*,则S10的值为( )
A.-110
B.-90
C.90
D.110
考点分析:
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的图象为C,
①图象C关于直线
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对称;
②函数在区间
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③由y=3sinx的图象向右平移
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个单位长度可以得到图象C
以上三个论断中,正确论断的个数是( )
A.0
B.1
C.2
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已知数列{a
n}为等差数列,数列{b
n}是各项均为正数的等比数列,且公比q>1,若a
1=b
1,a
2011=b
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1006与b
1006的大小关系是( )
A.a
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1006C.a
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1006D.a
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,1]∪[2,3)
B.[-1,
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,
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]
C.[-
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D.(-
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,3)
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已知向量
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=(2,1),
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+
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|=
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A.
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B.
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C.5
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2-3x+2≠0”
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2-3x+2=0”的充分不必要条件
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∈R,x
2+x
+1<0.则¬p:∀x∈R,x
2+x+1≥0
D.若p∧q为假命题,则p、q均为假命题
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