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已知等比数列{an}中,a2=2,则前3项的和S3的取值范围是( ) A.(-∞...
已知等比数列{an}中,a2=2,则前3项的和S3的取值范围是( )
A.(-∞,-2]∪[6,+∞)
B.[6,+∞)
C.(-∞,0]∪[6,+∞)
D.(-∞,-2]
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