the question is :

Determine whether the integral test can be used to determine the convergence or divergence of the following series. If it can be used, use it to determine the convergence or divergence. If the integral test can not be used, explain why.

$\displaystyle \sum_{n = 0}^{\infty} \frac{\cos(n)}{n}$

what i see is that

$\displaystyle -1\leq\cos(x)\leq1$

so

$\displaystyle \frac{-1}{x}\leq\frac{\cos(x)}{x}\leq\frac{1}{x}$

so because it is not always positive we can not use the integral test.... is this correct?