<p>Does anyone know which convergence test I should use for this problem? It's supposed to diverge... </p>
<p>The sum of the terms of (cos(n x pi))/((n+1)ln(n+1)) from n = 1 to n = infinity.</p>
<p>Thanks!</p>
<p>The cosine part is either +1 or -1, so this is an alternating series and the alternating series test suggests that this series <em>converges</em> . So, I too am confused :)</p>
<p>Nevermind! It actually converges conditionally! Sorry about that.</p>