问题
填空题
两个等差数列{an}和{bn}的前n项和分别为Sn和Tn，若
|
答案
∵
=Sn Tn 7n+3 n+3
∴
=a8 b8
=2a8 2b8
=a1+a15 b1+b15
(a1+a15)15 2
(b1+b15)15 2
=
=S15 T15
=67×15+3 15+3
故答案为：6
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两个等差数列{an}和{bn}的前n项和分别为Sn和Tn，若
|
∵
=Sn Tn 7n+3 n+3
∴
=a8 b8
=2a8 2b8
=a1+a15 b1+b15
(a1+a15)15 2
(b1+b15)15 2
=
=S15 T15
=67×15+3 15+3
故答案为：6