设Sn为等比数列an前n项和,2a3+a4=0,则S3/a1=?3

设等比数列{an}的公比为q=2,前n项和为{Sn},求S4/a3的值 设Sn为等比数列an前n项和,2a3+a4=0,则S3/a1=?3 设sn为等比数列an的前n项和,2a3-a4=0,S5/a1= 设等比数列{an}的前n项和为sn,若s2n=4(a1+a3+l+a(2n-1),a1a2a3=8,则a5= 设数列an是等比数列,其前n项和为Sn ,且Sn=3a3 求公比q 设数列an的前n项和为Sn,且2an=Sn+2n+1 求a1 a2 a3 求证:数列{an+2}是等比数列 求数列{n*an}的前n项和Tn 设数列an的前n项和为Sn,且2an=Sn+2n+1 求a1 a2 a3 求证:数列{an+2}是等比数列 求数列{n*an}的前n项和Tn 已知正数数列{an},其前n项和Sn满足10Sn=an^2+5an+6,且a1,a3,a15成等比数列,（1）求数列{an}的通项(通项为an=5n-3) （2）设bn=2/[an*a(n+1)],Sn是数列{bn}的前n项和,求使Sn 设数列{an}的前n项和为Sn,S1,S2,S3.Sn成等比数列,试问a2,a3.an成等比数列吗?证明你的结论. 记等差数列an的前n项和为Sn,设S3=12,且2a1,a2,a3+1成等比数列,求Sn 记等差数列{an}的前n项和为Sn,设S3=12,且2a1、a2、a3+1成等比数列,求Sn 记等差数列{an}的前n项和为Sn.设S3=12,且2a1,a2,a3+1成等比数列,求Sn 等差数列｛an｝的前n项和为Sn,设S3=12,且2a1,a2,a3 1成等比数列,求Sn? 等差数列an的前n项和为Sn,设S3=122,且2a1.a2.,a3+1成等比数列,求Sn 已知等比数列前n项和为Sn,a1a2a3...a*n=Pn,1/a1+1/a2+1/a3+...+1/an.求证：（Pn)^2=(Sn/Tn)^n 已知等比数列an的首项为a,公比q大于0,设这个数列前n项和为sn,记Tn=a1+a3+a5+……a（2n-1）求lim（Sn）/Tn 设数列{an}的前n项和为Sn,已知S1=1,Sn+1/Sn=n+c/n（c为常数,c不等于1,n属于正整数）设数列{an}的前n项和为Sn,已知S1=1,Sn+1/Sn=n+c/n,且a1,a2,a3成等差数列.c=2,an=n若数列{bn}是首项为1,公比为c的等比数列,记A 设数列{an}前n项和为Sn,已知a1+2a2+3a3+...+nan=(n-1)Sn+2n,（1）求a2,a3的值；（2）求证：数列{Sn+2}是等比数列.