limn→∞C12+C23+…+Cn-1nC22+C23+…+C2n=______.-数学

题目简介

limn→∞C12+C23+…+Cn-1nC22+C23+…+C2n=______.-数学

题目详情

lim
n→∞
C12
+
C23
+…+
Cn-1n
C22
+
C23
+…+
C2n
=______.
题型:填空题难度:中档来源:不详

答案

lim
n→∞
C12
+
C23
+…+
Cn-1n
C22
+
C23
+…+
C2n

=
lim
n→∞
class="stub"2+3+…+n
C2n+1

=
lim
n→∞
class="stub"n-1
2
(n+2)
n(n+1)
2

=
lim
n→∞
n2+n-2
n2+n

=1.
故答案为:1.

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