已知Sn是等差数列an(n∈N*)的前n项和,若S7>S5,则( )
已知等差数列{an}的前n项和为Sn,若2a6=a8+6,则S7是( )
Sn是等差数列{an}的前n项和,已知a2=3,a6=11则S7等于几
设Sn是等差数列an的前n项和,已知a2=3,S11=121,则S7等于
设Sn是等差数列{an}的前n项和,已知a1=3,a2=11,则S7等于?
设Sn是等差数列{an}的前n项和,已知a2=3,S11=121,则S7=
设Sn是等差数列{an}(n∈N+)的前n项和,且a1=1,a4=7,则S5=______.
以Sn表示等差数列{an}的前n项和,若S5>S6,证明:
已知等差数列{an}的前n项的和为Sn,且S2=10,S5=55,则过点P(n,an)和Q(n+2,an+2)(n∈N*
设Sn是等差数列{an}的前n项和,若S7=35,则a4=______.
设Sn是等差数列[an}的前n项和,若S7=5,则a4=
等差数列{an}的前n项和为Sn,已知S4=S5=-20,若Sn>0则n的最小值为?
已知等差数列{an}的前n项和Sn满足S3=0,S5=-5,