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已知数列{an}的通项an=27-2n(n∈N*),若bn=log2an,则数列...
已知数列{an}的通项an=27-2n(n∈N*),若bn=log2an,则数列{bn}的前n项和Sn中最大的是( )
A.S6
B.S5
C.S4
D.S3
考点分析:
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=
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•
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=2
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,且∠BAC=30°,则△OBA的面积为( )
A.
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