等差数列{an}的各项均为正数,a1=3,前n项和为Sn,{bn}为等比数列,b1=1,且b2*S2=64,b3*S3=960.求an,bn.求和1/S1+1/S2+...Sn
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![等差数列{an}的各项均为正数,a1=3,前n项和为Sn,{bn}为等比数列,b1=1,且b2*S2=64,b3*S3=960.求an,bn.求和1/S1+1/S2+...Sn](/uploads/image/z/3623459-59-9.jpg?t=%E7%AD%89%E5%B7%AE%E6%95%B0%E5%88%97%7Ban%7D%E7%9A%84%E5%90%84%E9%A1%B9%E5%9D%87%E4%B8%BA%E6%AD%A3%E6%95%B0%2Ca1%3D3%2C%E5%89%8Dn%E9%A1%B9%E5%92%8C%E4%B8%BASn%2C%7Bbn%7D%E4%B8%BA%E7%AD%89%E6%AF%94%E6%95%B0%E5%88%97%2Cb1%3D1%2C%E4%B8%94b2%2AS2%3D64%2Cb3%2AS3%3D960.%E6%B1%82an%2Cbn.%E6%B1%82%E5%92%8C1%2FS1%2B1%2FS2%2B...Sn)
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等差数列{an}的各项均为正数,a1=3,前n项和为Sn,{bn}为等比数列,b1=1,且b2*S2=64,b3*S3=960.求an,bn.求和1/S1+1/S2+...Sn
等差数列{an}的各项均为正数,a1=3,前n项和为Sn,{bn}为等比数列,b1=1,且b2*S2=64,b3*S3=960.
求an,bn.
求和1/S1+1/S2+...Sn
等差数列{an}的各项均为正数,a1=3,前n项和为Sn,{bn}为等比数列,b1=1,且b2*S2=64,b3*S3=960.求an,bn.求和1/S1+1/S2+...Sn
b2*S2=q*(3+3+d)=64
b3*S3=q^2*(9+3d)=960
解得,q=8,d=2(q=40/3时,a2