已知等差数列{an}满足:a1=3,a4+a8=26,{an}的前n项和为Sn,
已知等差数列{an}满足a1=3.a4+a8=26,{an}的前n项和为Sn.求an及sn
已知Sn为等差数列an的前n项和 a1=25 a4=16
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}的前n项和记为sn,如果a4=-12,a8=-4
已知等差数列{an}满足,a1>0,5a8=8a13,则前n项和Sn取最大值时,n的值为( )
已知等差数列{An}的前n项和为Sn,a1+a3+a6+a8=10求S8的值
已知等差数列{an}满足a3=15,a4+a6=22,Sn为an的前n项和
已知等差数列{an}的前N项和为Sn,a1=-2/3,满足Sn+1/Sn+2=an(n大于等于2)
已知等差数列{an}的前N项和为Sn,a1=-2/3,满足Sn+1/Sn+2=an(n大于等于2),
已知等差数列{an}中,a1=-3,11a5=5a8,求前N项和Sn的最小值
已知等差数列{an}满足:a3=7,a1+a11=26,{an}的前n项和为Sn,求an及Sn
已知前n项和为Sn的等差数列{an}的公差不为零,且a2=3,又a4,a5,a8成等比数列