等比数列{an}的前n项和Sn=2*3^(n+1)+k,首项a1=
等比数列{an}的前n项和Sn=2*3^(n+1)+k,首项a1=
an的前n项和Sn,a1=1,an+1=(n+2)/nSn,证数列Sn/n是等比数列和Sn+1=4an
数列An的前n项和为Sn,已知A1=1,An+1=Sn*(n+2)/n,证明数列Sn/n是等比数列
等比数列的证明方式数列An的前n项和为Sn,A1=1,A(n+1)=2Sn+1,证明数列An是等比数列
Sn是等比数列{an}的前n项和,且Sn=2^n+K,则实数K=?
数列{an}的前n项和为Sn,已知a1=1,an+1=(n+2/n)Sn(n=1,2,3,…)求证{Sn/n}是等比数列
等比数列{an}中,a1=2,前n项和为Sn,若数列{Sn+1}也是等比数列,求前n项和Sn
等比数列an的前n项和为sn,sn=1+3an,求:an
设等比数列{an}的前n项和为Sn,已知a1=2011,且an+2an+1+an+2=0(N∈N*),则S2012?
设数列An的前n项和为Sn,已知a1=1,An+1=Sn+3n+1求证数列{An+3}是等比数列
已知等比数列{an}的首项a1=2,公比q=3,Sn是它的前n项和.求证:Sn+1/Sn
等比数列前n项和Sn=k*3^n +1,则k的值为