等比数列{an}的首项a1=-1.前n项和为Sn,若.则Sn等于 ( ) C 2 D -2 查看更多

 

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等比数列{an}的首项a1=-1,前n项和为Sn,若=,则Sn等于

A.                            B.-                         C.2                              D.-2

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等比数列{an}的首项a1=-1,前n项和为Sn,若,则Sn等于              

A.               B.-             C.2                D.-2

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等比数列{an}的首项a1=-1,前n项和为Sn,若,则Sn等于(  )

               C. 2                            D. -2

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等比数列{an}的首项a1=-1,前n项和为Sn,若,则Sn等于(  )
               C. 2                            D. -2

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数列{an}的首项a1=1,前n项和为Sn,满足关系3tSn-(2t+3)Sn-1=3t(t>0,n=2,3,4…)

(1)求证:数列{an}为等比数列;

(2)设数列{an}的公比为f(t),作数列{bn},使b1=1,bn=f().(n=2,3,4…)求bn

(3)求Tn=(b1b2-b2b3)+(b3b4-b4b5)+…+(b2n-1b2n-b2nb2n+1)的值

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