已知sn=32n-n^2求等差数列|an|的前n项和sn

已知sn=32n-n^2求等差数列|an|的前n项和sn 已知等差数列前n项和 sn=2n^2+3n求an {an}是等差数列,Sn=n2-2n,求：an 已知等差数列{an}的前n项和是sn=32n一n*n,求{|an|}的前n项和sn 已知一等差数列{an}的前n项和Sn=n^2-3n+1,求an 在等差数列中,已知d=2,an=1,sn=8求an,n 已知等差数列{an}的通项公式an=2n+1,求Sn 已知在数列an中,Sn=2n^2+3n,求证an是等差数列并且 求an 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 已知{an}为等差数列,Sn为其前n项喝,且2Sn=an+2n²(1)求an.Sn 已知等差数列an中,a1=1,前n项和Sn,若S(n+1)/Sn=(4n+2)/(n+1),求an 已知等差数列an中,a1=1,前n项和Sn,若S(n+1)/Sn=(4n+2)/(n+1),求an 已知等差数列{An}中,Sn=m,Sm=n(m≠n),求Sm+n 已知等差数列{an}的前n项和Sn=n²求an 数列{an}的前n项和为Sn,已知a1=1/2,Sn=n^2an-n(n-1) (1)证明：数列{（n+1)/n*Sn}是等差数列,求Sn 等差数列{an}前n项和为Sn=3n-2n^2,求an 已知等差数列{an}中,an=4^n-1 +n,n属于n,(1)求数列{an}的前n项和sn(2)证明不等式sn+1小于等于4sn,对任意n属于正整数皆成立 已知等差数列｛an｝前n项和Sn=n平方-20n,求｛|an|｝前n项和Tn.已知等差数列｛an｝前n项和Sn=n²-20n,求｛|an|｝前n项和Tn.