等差数列（an),前n项和为Sn.(1)Sm=n,Sn=m.求Sm+n的值（2）Sm=Sn(m不等于n)求Sm+n的值

设Sn为等差数列an的前n项和.求证Sn/n为等差数列 等差数列前n项和为Sn=1/2(An+1/An),求通项An 等差数列{an}的前n项和为sn,a10 等差数列{an}前n项和为sn,求证S2n-1=(2n-1)an 设Sn为等差数列{An}的前n项和,求证：{Sn/n}是等差数列 (1)已知数列an的前n项和为sn满足sn=an²+bn,求证an是等差数列(2)已知等差数列an的前n项和为sn,求证数列sn/n也成等差数列 等差数列前n项和为Sn,求证:S2n-1=(2n-1)an 等差数列{an}前n项和为Sn=3n-2n^2,求an 等差数列{an}=2n+1,前n项和为Sn,求1/S1+1/S2+.+1/Sn 等差数列前n项和为Sn,若a（n+1）=3Sn,a1=1,则通项an? 已知公差不为0的等差数列{An}的首项A1=1,前n项和为Sn,若数列{Sn/An}是等差数列,求An? 等差数列{an}前n项和为Sn,求证S 2n-1项=（2n-1）an 等差数列an前n项和为Sn,求证S（2n-1）=（2n-1）an 已知数列{an}的前N项和sn=n^2+n+1,an是否为等差数列? 设等差数列an前n项和为Sn,S2010-S1=1,S2011=? 等差数列{an}的通项公式an=1-2n,其前n项和sn,则数列{sn/n}的前11项和为? 已知等差数列{an}的前n项和为Sn,如果Sn=(an+1/2)^2(n∈N+0,bn=(-1)^n*Sn已知等差数列{an}的前n项和Sn,如果Sn=(an+1/2)^2(n∈N+0,bn=(-1)^n*Sn,试求{bn}的前n项和Tn 数列an ,a1=1,前n项和为Sn ,正整数n对应的n an Sn 成等差数列.1.证明{Sn+n+2}成等比数列,2.求{n+2/n(n+1)(1+an)}前n项和