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已知平面向量、的夹角为60°,则=(,1),||=1,则|+2|═( ) A.2...
已知平面向量
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、
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的夹角为60°,则
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=(
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,1),|
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|=1,则|
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+2
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|═( )
A.2
B.
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C.2
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D.2
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考点分析:
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的展开式中常数项是( )
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已知集合U=R,A={x|x
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A.{x|x<2或x>3}
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已知函数g(x)=ax
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有三个不同的实数解,求实数k的范围.
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定义x
1,x
2,…,x
n的“倒平均数”为
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,记c
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(n∈N
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T
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,3]).
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