问题
填空题
已知Sn,Tn分别是等差数列{an},{bn}的前n项和,且
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答案
∵Sn,Tn分别是等差数列{an},{bn}的前n项和,
且
=Sn Tn
,(n∈N+),2n+1 4n-2
∴
+a10 b3+b18
=a11 b6+b15 a10+a11 b10+b11
=
=S20 T20
=40+1 80-2
.41 78
故答案为:
.41 78
已知Sn,Tn分别是等差数列{an},{bn}的前n项和,且
|
∵Sn,Tn分别是等差数列{an},{bn}的前n项和,
且
=Sn Tn
,(n∈N+),2n+1 4n-2
∴
+a10 b3+b18
=a11 b6+b15 a10+a11 b10+b11
=
=S20 T20
=40+1 80-2
.41 78
故答案为:
.41 78