已知等差数列(an)满足条件a3+a5=2,前20项和A20=150.
已知等差数列{an}满足:a3+a4=16,a4+a5=20,{an}的前n项和为Sn
已知等差数列an满足a2+a4=-6,a3+a5=-2(1)求数列an的通项公式(2)求数列{|an|}的前n项和Tn
已知等差数列{An}满足:a3=7 ,a5+a7=26 ,{An}的前n项和为Sn
已知等差数列{an}满足:a3=7,a5+a7 =26,an的前n项和为sn.
1.已知等差数列{An}满足:A3=7,A5+A7=26,{An}的前n项和为Tn
已知等差数列{an}满足:a3=7,a5+a7=26.{an}的前n项和为Sn.
已知等差数列(an)满足:a3=7,a5+a7=26,(an)的前n项和为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;令bn=一除以an的平方减
已知等差数列{an}满足a2+a4=4,a3+a5=10,则它的前10项的和S10=( )
已知等差数列{an}满足:a3=7,a5+a7=26,{an}的前n项和为Sn.令bn=1/(an)^2-1(n∈N*)
已知等差数列an满足a3=7,a5+a7=26,an的前n项和为sn.1.求an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