等差数列{an}的前n项和为Sn,且6S5-5S3=5,则a4=______.
等差数列{an}的前n项和为Sn,且6S5-5S3=5,则a4=______.
等差数列an前n项和Sn且6S5-5S3=5,a4等于多少
已知等差数列{an}的前n项和为Sn,公差d≠0,且S3+S5=50,a1,a4,a13成等比数列.
已知等差数列{an}的前n项和Sn满足S3=0,S5=-5,
高一数学. 已知等差数列{an}的前n项和胃Sn,公差d≠0,且S3+S5=50,a1,a4,a13成等比数列.
设Sn是等差数列{an}(n∈N+)的前n项和,且a1=1,a4=7,则S5=______.
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,求{an}通项公式.
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
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 (2)若从数列
sn为等差数列an的前n项和 已知S3/S7=2/5 则a2/a4
已知公差不为0的等差数列{an}的前n项和为Sn,S3=a4+6,且a1,a4,a13成等比数列.
已知等差数列{an}的前n项和伟sn,公差d≠0,且s3+s5=50,a1,a4,a13城等比数列.求数