设等比数列{an}的前n项和为Sn,则“a1>0”是“S3>S2”什么条件?为什么呢?

设等比数列{an}的前n项和为Sn,则“a1>0”是“S3>S2”什么条件?为什么呢? 设数列{an}的前n项和为Sn,且an不等于0,S1,S2,S3 Sn成等比数列,试问a1,a2,a2是等比数列吗 设数列an的前n项和为sn,且an≠0,s1,s2,s3……成等比数列,则数列a1,a2,a3……成等比数列吗 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 设Sn是公差不为0的等差数列an地前n项和且S1,S2,S4成等比数列,则a1/a2等于 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. 设数列{an}是首项为a1(a1>0),公差为2的等差数列,前n项和为Sn,且根号S1,根号S2,根号S3成等差数列, 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.已知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 等比数列{an}的前n项和为Sn,已知S1,S3,S2成等差数列 已知sn是公差不为0的等差数列{an}的前n项和,且s1,s2,s3成等比数列,则a1分之a2+a3等于解题步骤 已知等差数列｛an｝前n项和为Sn,公差d≠0,且S3+S5=50,a1,a4,a13,成等比数列 设{bn/an}是首