设Sn是等差数列｛an｝的前n项和,求证：若正整数m,n,p成等差数列,则Sm/m,Sn/n,Sp/p也成等差数列.

设Sn为等差数列{An}的前n项和,求证：{Sn/n}是等差数列 设Sn为等差数列an的前n项和.求证Sn/n为等差数列 设Sn是等差数列｛an｝的前n项和,求证：若正整数m,n,p成等差数列,则Sm/m,Sn/n,Sp/p也成等差数列. 一道关于等差数列的题设Sn为等差数列｛An｝的前n项和 求证：数列｛n分之Sn}是等差数列 设Sn为等差数列前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 已知数列{an}的前n项和sn满足sn=an^2+bn,求证{an}是等差数列 设数列{an}的前n项和为Sn ,求证数列{an}成等差数列的充要条件是：对一切m,n∈N*,都有 设数列an的前n项和为sn,对于所有的自然数n都有sn=n(a1+an)/2,求证an是等差数列.请按照我的思路来做.设数列an的前n项和为sn,对于所有的自然数n都有sn=n(a1+an)/2,求证an是等差数列.我的思路为 an=sn-sn 已知数列{an}的前n项和Sn=32n-n²,求证数列{an}是等差数列已知数列{an}的前n项和Sn=32n-n²,（1）求证数列{an}是等差数列（2）设bn=|an|,求数列｛bn｝的前n项和Tn 设Sn是等比数列｛an｝的前n项和,s3,S9,S6,成等差数列求证:a2,a8,a5　成等差数列 设Sn是等比数列｛an｝的前n项和,s3,s9,s6,成等差数列求证:a2,a8,a5　成等差数列 设Sn是等差数列{an}的前n项和,且S5S8,则a1 已知数列{an}的前n项和为Sn=n^2-3n,求证：数列{an}是等差数列 已知数列｛an｝的前n项和sn=n方+3n,求证数列{an}是等差数列 关于等差数列的题设数列{An}的前n项和为Sn,已知A1=1,且满足3Sn^2=An(3Sn-1)(n≥2)(1)求证:数列{1/Sn}是等差数列(2)设bn=Sn/3n+1,求数列{bn）的前n项和n 设数列{an}的前n项和为Sn且a1=1,Sn+1=4an+2(n属于正整数) （1）设bn=an/2n,求证数列{bn}是等差数列 （2设数列{an}的前n项和为Sn且a1=1,Sn+1=4an+2(n属于正整数)（1）设bn=an/2n,求证数列{bn}是等差数列（2）求 设数列{an}的前n项和为Sn,a1=1,an=sn/n+2(n-1),求证数列{an}是等差数列,并求其通项公式an