在等比数列{an}中的前n项和为Sn,且a1=负1,a4=64,则S4等于多少
等比数列an的前n项和为Sn,且4a1,2a2,a3成等差数列.若a1等于1,则S4为多少?
已知{an}是等差数列,其前n项和为sn,{bn}是等比数列,且a1=b1=2,a4+b4=27,s4-b4=10
已知{An}是等差数列,其前n项和为Sn,{Bn}是等比数列,且A1+B1=2,A4+Bb4=27,S4-B4=10
设等比数列an的公比为q=1/2,前n项和为Sn,则S4/a4=?
设等比数列{an}的公比q=1/2,前n项和为Sn,则S4/a4=
设等比数列an的公比q=1/2,前n项和为sn,则s4/a4=
设等比数列{an}的公比q=1/2,前n项和为Sn,则S4/a4=?
设等比数列an的公比q=1/2,前n项和为Sn,则S4/a4
等比数列{an}的前n项和为Sn,且4a1,2a2,a3成等差数列.若a1=1,则S4=( )
等比数列{an}的前n项和为Sn,且4a1,2a3,a3成等差数列,若a1=1,则S4=?
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q=2,前n项和为Sn,则S4/a2等于多少