设Sn是等差数列｛an｝的前N项和,诺S3/S6=1/3则S6/S12=多少

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,已知S8=108,Sn=630,S(n-8)=234,求n. 设Sn是等差数列{an}的前n项和,已知S8=108,Sn=630,S(n-8)=234,求n. 设Sn是等差数列{an}的前n项和,且S5S8,则a1 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{an}的前n项和,已知a6+a70,那么Sn中最小的是 设Sn为等差数列{an}的前N项和,已知 a6 +a70,那么Sn 中最小的是 设等差数列{an}的前n项和为Sn 若a1=Sn> {an}是等差数列,a1不等于0,Sn是它前n项的和.求lim (n→∞) (Sn+S(n+1))/(Sn+S(n-1)) 设等比数列an的公比为q,前n项和为sn,若s(n+1),sn,s(n+2)成等差数列,求q的值 设等比数列[an]的公比为q,前n项和为Sn,若S(n+1),Sn,S(n+2)成等差数列,则q的值? 设Sn是等差数列an的前n项和,a5=2,an-4=30(n≥5,n∈N*),Sn=136,求n 设等比数列 ｛an｝ 的公比为q,前n项和为Sn,若S(n+1),Sn,S(n+2)成等差数列,则q= 设Sn为等差数列{an}的前n项和,已知s6=36,Sn=324 ,S(n-6)=144 ,(n>6) ,求n的值 设Sn是等差数列{an}的前n项和好,已知S6=36,Sn=324,S(n-6)=144,n>6,则n= 设等差数列{an}公差d是2,前n项和为Sn,则lim(an^2-n^2)/Sn