# Convergence test

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• November 26th 2007, 06:54 AM
partyshoes
Convergence test
Hi Folks

I need to find out if the series converges: cos n/n^3. I think it is a harmonic series becouse of the power on the denomimator but how do I combine this with sinusiodal cos n?

Has anyone ever seen this before?:p
• November 26th 2007, 10:21 AM
ThePerfectHacker
$\left| \frac{\cos n}{n^3} \right| \leq \frac{1}{n^3}$