等差数列{an}中,Sn是前n项和,a3+a8>9,S9
设Sn是等差数列{an}的前n项和,若a5/a3=5/9,则S9/S5=:
在等差数列{an}中,Sn表示前n项和,a2+a8=18-a5,则S9=______.
关于等差数列基础题已知Sn是 等比数列An的前n项和,S3,S9,S6成等差数列,求证 A2,A8,A5成等差数列(步骤
已知Sn是等比数列{an}的前n项和,S3,S9,S6成等差数列,求证a2,a8,a5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,求证a2,a8,a5成等差数列
已知Sn是等比数列an中的前n项和,S3.S9.S6成等差数列,求证a2.a8.a5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.求证A2 A8 A5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,求证a2,a8,a5 成等差数列.
设Sn是等比数列{an}的前n项和,s3,S9,S6,成等差数列求证:a2,a8,a5 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,求证:a2,a8,a5成等差数列.
设Sn是等比数列的前n项和,S3,S9,S6成等差数列 求证a2,a8,a5成等差数列
设Sn是等差数列{an}的前n项和,若a5/a3=5/9,则S9/S5值为?