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已知等差数列{an}中,前n项和为Sn,若a3+a9=6,则S11等于( ) ...
已知等差数列{an}中,前n项和为Sn,若a3+a9=6,则S11等于( )
A.12
B.33
C.66
D.11
考点分析:
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