已知等差数列{an}满足a2+a4=4,a3+a5=10,求{an}的通项公式及{an}的前n项和sn
已知等差数列{an}满足a2+a4=4,a3+a5=10,求{an}的通项公式及{an}的前n项和sn
已知等差数列【an】满足:a3=7,a5+a7=26.【an】的前n项和为Sn.(1)求a4及Sn;
已知等差数列{an}满足a3=7,a5+a7=26{an}的前n项和为Sn求a4及Sn
已知等差数列{an}满足:a3+a4=16,a4+a5=20,{an}的前n项和为Sn
已知数列{an}是等差数列,它的前n项和为Sn.a1+a2+a3=4,a3+a4+a5=10.求SN
已知等差数列{an}满足:a3=7,a5+a7=26,{an}的前n项和为Sn.求an及Sn.
已知等差数列{an},a3=7.a5+a7=26.{an}的前n项和为Sn.1.求a4及Sn.
等差数列{an}中,a1+a3=12,a2+a4=6,求这个数列的通项公式an及它的前n项和Sn.
等差数列{An}的前n项和为Sn,且满足A3*A4=117,A2+A5=22 求通项An ;若数列{Bn}是等差数列,且
已知公差大于零的等差数列{an}的前n项和为Sn,且满足:a3•a4=117,a2+a5=22.
已知公差大于零的等差数列{an}的前n项和Sn,且满足a3*a4=117,a2+a5=22
已知公差大于零的等差数列{an}的前n项和为Sn,且满足:a3*a4=117,a2+a5=22