Question

Determine whether the series is absolutely convergent, conditionally convergent or divergent.

series in comments

Answer 1

\[\sum_{n=1}^{\infty} \frac{ (-1)^n }{ n^4+1 }\]

Answer 2

@electrokid

Answer 3

i know the ratio test is inconclusive

Answer 4

did you try the limit test?

Answer 5

Who needs ratio tests? Just use a direct comparison :D