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Mathematics
Problem
In one or two sentences, explain why the series
∑
n
=
1
∞
(
−
1
)
n
+
1
n
\displaystyle\sum_{n=1}^{\infty}\frac{(-1)^{n+1}}{n}
n
=
1
∑
∞
n
(
−
1
)
n
+
1
converges but its corresponding series of absolute values does not.
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