1. The problem statement, all variables and given/known data Use the Integral Test to determine convergence or divergence of the series: ∞ Ʃ ln(n)^-4 n=2 2. Relevant equations Integral Test d/dx ln(x)=1/x f(x)=ln(x)^-4 3. The attempt at a solution I understand how to apply the Integral test. I just am having a difficult time finding the integral of f(x). I tried using u-substitution, where u=ln(x) du=(1/x) dx dx=xdu When I try to plug in the substitutions for u and du, I am left with the improper integral ∫x/u^4 du from 2 to Infinity Since the x is still in there, I can't continue with the substitution. Is there another way to go about solving the integral? Am I approaching the u-substitution wrong?