化简Sn-Sn-1
an是等差数列,求lim (Sn+Sn+1)/(Sn+Sn-1)
已知等差数列{an}的前n项和为Sn,且a1不等于0,求(n*an)/Sn的极限、(Sn+Sn+1)/(Sn+Sn-1)
Sn=3+2^n Sn-1=3+2^(n-1).则Sn-Sn-1=?
已知数列{an}的前n项和为Sn,且满足Sn=Sn-1/2Sn-1 +1,a1=2,求证{1/Sn}是等差数列
已知数列an是等差数列,且a1不等于0,Sn为这个数列的前n项和,求limnan/Sn.limSn+Sn-1/Sn+Sn
SN是什么意思?
等差数列sn
正项无穷等比数列{an}前n项和为Sn,lim(Sn/Sn+1)=1 求公比范围
已知数列 an前n项和为Sn,a1=1,Sn=2a(n+1),求Sn
数列{an}前n项和为Sn,且2Sn+1=3an,求an及Sn
求和:Sn=1+(1+12
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