See http://www.wolframalpha.com/input/?i...+n-%3Einfinity.
This is a sequence, not a series.
I need to prove that this converges to 0.
I have thought about trying a proof by contradiction, and the comparison test (cos(n^3)/n^3) is always smaller than 1/n^3.
I have thought about breaking up the limit into individual parts, but I still get 0 times a divergent.
Thank you.