等比数列{an}共2n项,前2n项和为-240,且奇数项和比偶数项和大80,求公比q.
已知等比数列{an}共有2n项,其和为-240,且奇数项的和比偶数项的和大80,则公比q=______.
设等比数列{an}的公比q=2,前n项和为Sn,S4\a2
已知等比数列{an}前n项和为sn,且s4/s2=15/2,则公比q等于
设等比数列an的公比为q,前n项和为sn,若s(n+1),sn,s(n+2)成等差数列,求q的值
等比数列{an},an>0,Sn=80.S(2n)=6560,且前n项和中数值最大项为54,求首项a1,公比q
设等比数列{an}公比为q,前n项和Sn>0(n=1,2,3…)(1)求q的取值范围?
设等比数列{an}的公比为q,前n项和为Sn,且a1>0,若s2>2a3,则q的取值范围是
已知等比数列{An}的公比为q,前n项和为Sn,且S3,S9,S6成等差数列
已知等比数列{An}的公比为q,前n项的和为Sn,且S3,S9,S6成等差数列.
等比数列{an}的首项a1=-1,公比为q,前n项和为Sn,若S10/S5=31/32.(1)求公比q;(2)求前n项和
已知等比数列{an}的公比为q,前n项和为Sn,求[Sn*Sn+2-(Sn+1)^2]/[an*an+2]
设等比数列an的公比为q=1/2,前n项和为Sn,则S4/a4=?