等差数列{an},前n项和为Sn,若S2=2,S4=10,则S6为多少?

等比数列{an},前n项和为Sn,若S1,2S2,3S3成等差数列,求{an}的公比 等差数列{an},前n项和为Sn,若S2=2,S4=10,则S6为多少? 等差数列{an}=2n+1,前n项和为Sn,求1/S1+1/S2+.+1/Sn 等差数列 an的前n项和为sn ,若s2=4,s4=20,则公差d= 等差数列｛an｝的前n项和为sn,若s2=2,s4=10,则s6=? 等差数列｛an｝的前n项和为sn,若s2=2,s4=10,则s6=? 等差数列{an}的前n项和为Sn,若S2=2,S4=10,则S6等于? 等差数列｛an｝的前n项和为Sn,若S2=2,S4=10,则S6等于多少? 等差数列{an }的前n项和为sn,若s2=2,s4=10,则s6等于 等差数列{an}的前n项和为Sn,若S2=2,S6=24,则S4等于 等比数列{an}的前n项和为Sn,已知S1,S3,S2成等差数列1 ,求｛an｝的公比q2 ,若a1-a3=3求Sn 等比数列an的前n项和为sn 已知s1 s3 s2成等差数列 求an的公比q 求若a1-a3=3 求sn 等比数列an前n项和sn满足s1,s3,s2成等差数列,求sn 设等差数列An的前n项和为Sn,且S4=4S2,A2n=2An+1 等比数列{an}的前n项和为Sn.S1.2S2.3S3诚等差数列,则{An}的公比 、已知{an}为等差数列,Sn为其前n项的和,若a1=1/2,S2=a3,则a2=____,Sn=_____ 帮个忙,关于数列的题已知an为等差数列sn为其前n项和,若a1=3,S2=a3,则a3=();Sn=() 若在等比数列{an}中,前n项和为Sn,若a2,a4,a3成等差数列,判断S2,S4,S3是否成等差数列,并给出证明.