已知sn为等差数列an的前n项和,Sn=12n-n²,求|a1|+|a2|+|a3|+···+|an|

(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 已知等差数列an中,前n项和sn=n^2-15n,则使sn为最小值的n 已知sn=32n-n^2求等差数列|an|的前n项和sn 等差数列an的前n项和为Sn,已知Sm=a,Sn-Sn-m=b,m、n属于自然数且n>m,求Sn? 已知数列{an}的前n项和为Sn,且满足an+2Sn*Sn-1=0,a1=1/2.求证：{1/Sn}是等差数列 等差数列an的前n项和为Sn,已知a5=11 a8=5求an和Sn 已知an是等差数列,前n项和为Sn,求证:S3n=3(S2n-Sn) 已知等差数列{An}的前n项和为Sn,已知A1=25 S9+S17 求Sn最大值 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 设Sn为等差数列an的前n项和.求证Sn/n为等差数列 设等差数列{an}的前n项和为Sn 若a1=Sn> 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-1 设Sn为等差数列{An}的前n项和,求证：{Sn/n}是等差数列 等差数列{an}的前n项和记为Sn,已知S6=36,Sn=324,Sn-6=144(n>6),则n等于? 已知Sn为等差数列an的前n项和,a6=100,则S11= 已知Sn为等差数列｛an｝的前n项和,S11=55,则a6= 设等差数列{an}的前n项和为Sn,已知a3=11,S15*S16 已知等差数列{an}的前n项和为Sn,则S7-S3除以S10=