设Sn是等差数列{an}的前n项和,若a5a3=59,则S9S5=______.-数学

题目简介

设Sn是等差数列{an}的前n项和,若a5a3=59,则S9S5=______.-数学

题目详情

设Sn是等差数列{an}的前n项和,若
a5
a3
=
5
9
,则
S9
S5
=______.
题型:填空题难度:中档来源:不详

答案

S9
S5
=
(a1+a9)×9
class="stub"2
(a1+a5)×5
2
=
a5
a3
×class="stub"9
5
=1
故答案为1

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