已知等比数列An前N项和为Sn,S2=30,S3为155,求Sn.
已知等比数列An前N项和为Sn,S2=30,S3为155,求Sn.
等比数列{an}的前n项和为Sn,已知S1,S3,S2成等差数列,求{an}的公比Q.已知a1-a3=3,求sn?
等比数列{an}的前n项和为Sn,已知S1,S3,S2成等差数列
等比数列{an}的前n项和为Sn,已知S1,S3,S2成等差数列
等比数列{an}的前n项和为Sn,已知S1,S3,S2成等差数列,求{an}的公比q
等比数列{an}的前n项和为Sn,已知S1,S3,S2成等差数列.①求公比q②a1-a3=3,求Sn
设数列{an}的前N项和为Sn,已知1/Sn+1/S2+1/S3+.+1/Sn=n/(n+1),求Sn
已知等比数列{an}的前n项和为sn,a1=2,s1,2s2,3s3成等差数列,1.求数列{an}的通项公式
等差数列{an}的前n项和为Sn.已知S3=a22,且S1,S2,S4成等比数列,求{an}的通项式.
已知等差数列{an}的公差为2,前n项和为sn,且s1,s2,s3,s4成等比数列
等差数列{An}前n项和为{Sn},且S1,S2,S3成等比数列.
已知等比数列{an}的前n项和为Sn,满足a3=2S2+1,a4=2S3+1,求公比q