等差数列{an}的前n项和为Sn,若S3=S6,则S9=______.
已知正项等比数列{an}的前n项和为Sn,若S3=3,S9-S6=12,则S6=______.
设等比数列an的前n项的和为Sn,若S6/S3=3,则S9/S6=
1.设等比数列{an}的前n项和为Sn,若S6/S3=3,则S9/S6=?
设等比数列{an}的前n项和为Sn,若S6:S3=1:2,则S9:S3=?
设Sn是等比数列{an}的前n项和,S3,S9,S6成等差数列,则公比q=______.
等比数列{an}的前n项和为sn,若s3+s6=2s9,则数列的公比为______.
填空题等差数列{an}的前n项和为Sn,若S3=3,S6=9,则S9=( ).
设Sn是等比数列{an}的前n项和,S3,S9,S6成等差数列.
已知Sn是等比数列{An}的前N项和,S3,S9,S6成等差数列,则
等比数列{an}的前n项和为sn,若S3,S9,S6成等差数列,求此数列的公差,
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=( )
设等比数列{an}的前n项和为sn,若S6,S9,S3成等差数列,问2S3,S6,S12-S6S能否成等比数列?请说明理