Correct Answer!
By the :
Consider the series
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¥ å
n = 1
|
| an| = |
¥ å
n = 1
|
|
arctan(n)
n2+1
|
|
|
and compare it to the convergent p-series (p=2) multiplied by
a constant:
Since for n ³ 1
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arctan(n)
n2+1
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£ |
p/2
n2+1
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£ |
p
2
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æ ç è
|
|
1
n2
|
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ö ÷ ø
|
|
|
then the implies convergence of the series.
Note that this problem can also be solved using the Integral Test and
Limit Comparison Test.