I'm trying to test the summation $\sum^\infty_{n=0}\frac{(-1)^n}{5n+1}$ for absolute convergence.
By alternating series test, I can tell is is at least conditionally convergent.
However, when I used the ratio test, I got 1, which means it doesn't tell us anything.
A google search showed an answer on yahoo answers using the limit comparison test, using the harmonic series to compare it with, but they seemed to ignore the $(-1)^n$...
The answer in the book says it is conditionally convergent, but I can't work out how to show that it is not absolutely convergent.
Any ideas?
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