已知数列an,an属于n*,sn=1/8*(an+2)^2,{an}是等差数列
已知数列{an}中,a2=2,前n项和为Sn,且Sn=n(an+1)/2证明数列{an+1-an}是等差数列
求此数列题详细解法已知数列an Sn=1/8(an+2)^2 求证an是等差数列
已知在数列an中,Sn=2n^2+3n,求证an是等差数列
已知数列{an}满足2an/an+2=an+1(n属于正整数),a1=1/1006.求证:数列{1/an}是等差数列,并
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
已知正项数列an的前n项和为Sn,a1=1,(an-2)²=8Sn-1.证明an是等差数列.
已知数列{an}满足Sn=2n-an(n属于N*),证明{an-2}是等比数列
已知数列{An}满足A1=1,An+1=2An+2^n.求证数列An/2是等差数列
设数列{An}满足,A1=1,An+1=3An,n属于N+.(1)求An的通项公式及前n项和Sn(2)已知bn是等差数列
已知数列{an}前n项和为Sn,对于n属于自然数,总有Sn=(a1+an)n/2,求证{an}为等差数列.
在等差数列{an}中,a1=1,a2=3,an+2=3an+1-2an(n属于N+)证明数列{an+1-an}是等比数列
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