已知等差数列{an }中,an≠0,且 an-1-an2+an+1=0,前(2n-1)项和S2n-1
已知等差数列{an }中,an≠0,且 an-1-an2+an+1=0,前(2n-1)项和S2n-1
已知数列{an}中,an>0且an2-2anSn+1=0,其中Sn为数列{an}的前n项和.
已知数列{an}的前n项的和Sn,满足6Sn=an2+3an+2且an>0.(1)求首项a1;(2)证明{an}是
已知{an}中,an>0,Sn是{an}的前n项和,且an+1/an=2Sn,求an.
数列{an}中,an 1=an2/2an-5,且这数列既是等差数列又是等比数列,则{an}的前20项之
等差数列{an}a1=1前n项和为Sn且S2n/Sn=4n+2/n+1 (1)求an通项公试
已知数列an是各项均不为0的等差数列,Sn为其前n项和,且满足S2n-1=1/2an^2,数列bn满足,当n为奇数时bn
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
等差数列an中,a1=1前n项和Sn,满足条件S2n/Sn=4n+2/n+1,求an通项 记Bn=anp^an(p>0)
等差数列an中,a1=1前n项和Sn,满足条件S2n/Sn=4n+2/n+1,求an通项
已知各项均为正数的数列an中,a1=1,Sn为数列an的前n项和 若数列{an}{an2}都是等差数列,求数列{an}的
等差数列{an},a1=1,前n项和Sn,S2n/Sn=4