设等比数列{an}公比为q,a1不等于0,前n项和为sn,若s3,s9,s6成等差数列,求公比q.

来源：学生作业帮编辑：作业帮分类：数学作业时间：2024/05/17 01:12:21

（1）若q=1,则S3 =3a ,S9 =9a ,S6 =6a;不成等差数列
故q≠1,此时由S3 ,S9 S6 成等差数列得
2S9 = S3 + S6 ,
2*a1(1-q^9)/(1-q)
=a1(1-q)^3/(1-q)+a1(1-q^6)/(1-q)
化简得：2q^6-q^3-1=0
所以q=- (1/2)^(1/3

设等比数列{an}公比为q,a1不等于0,前n项和为sn,若s3,s9,s6成等差数列,求公比q. 已知Sn是等比数列{an}的前n项和,设公比为q,且S3,S9,S6成等差数列. 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. 设Sn是等比数列的前n项和,若S3,S9,S6成等差数列,这an的公比q为多少等比数列｛an｝的公比为q,其前n项和为Sn,若S3,S9,S6成等差数列,则q＾3＝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.（1）求q3的值已知等比数列{an}的公比为q,前n项和为Sn,且 S3,S9,S6 成等差数列,则q^3=( ) 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,则q的三次方等于多少, 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,给出下列结论：①a3,a9,a6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.则q3的值是（　　）已知等比数列｛αn｝的公比为q(q为实数）,前n项和为Sn,且S3,S9,S6成等差数列,则q3等于什么?