MathDB
Problems
Contests
Undergraduate contests
Putnam
1988 Putnam
B4
B4
Part of
1988 Putnam
Problems
(1)
Putnam 1988 B4
Source:
8/6/2019
Prove that if
∑
n
=
1
∞
a
n
\sum_{n=1}^\infty a_n
∑
n
=
1
∞
a
n
is a convergent series of positive real numbers, then so is
∑
n
=
1
∞
(
a
n
)
n
/
(
n
+
1
)
\sum_{n=1}^\infty (a_n)^{n/(n+1)}
∑
n
=
1
∞
(
a
n
)
n
/
(
n
+
1
)
.
Putnam
Convergence