问题
填空题
等差数列{an},{bn}的前n项各分别为Sn,Tn且
|
答案
等差数列中S2n-1=(2n-1)•an,∵
=Sn Tn 3n-1 2n+3
∴
=a9 b9
=S17 17 T17 17
=S17 T17
=3×17-1 2×17+3
,50 37
故答案为:
;50 37
等差数列{an},{bn}的前n项各分别为Sn,Tn且
|
等差数列中S2n-1=(2n-1)•an,∵
=Sn Tn 3n-1 2n+3
∴
=a9 b9
=S17 17 T17 17
=S17 T17
=3×17-1 2×17+3
,50 37
故答案为:
;50 37