已知等差数列{an}的公差d>0,设{an}的前几项和为Sn,a1=1,S2×S3=36,求m,k(m,k∈N*)
已知等差数列{an}的公差d>0,设{an}的前几项和为Sn,a1=1,S2×S3=36,求m,k(m,k∈N*)
已知等差数列{an}的公差d>0,设{an}的前n项和为Sn,a1=1,S2•S3=36.
设Sn为等差数列{an}的前n项和,若a1=1,公差d=2,Sk+1-Sk=24,求K=多少?
等比数列{an}中,前n项和为sn,已知S1,S3,S2成等差数列.问:若a1-a3=3,求数列S1、S3、S2的公差d
设a1 d 为实数 首项为a1 公差为d的等差数列an前n项和为Sn 满足 S2*S6+15=0 ,
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,
设Sn为等差数列{an}的前n项和,若a1=1,公差d=2,Sk+2-Sk=24,则k=?
设Sn为等差数列{an}的前n项和,若a1=1,公差d=2,Sk+2-Sk=24,则k=( )
设等差数列{an}的前n项和为Sn 已知S3=S12 则当公差d
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
设等差数列{an}前n项的和为Sn,已知a3=12,S12>0,S13<0 求公差d的取值范围;指出S1,S2,S3……
等差数列an的前几项和为Sn,已知S3=6,a1=11,则公差d等于