Veritas

Thanks for your quick response, but don't quite understand what you mean by "Use the fact that u+1 divides any polynomial of the form un+1". I'm from Holland so maybe you're using different terminology than I'm used to but could you please explain me that part a bit more?

Hi everyone! This is my first post on this site so if I'm breaking any rules I appolgize in advance. For an opcoming physics entrance exam i'm repolishing my math skills but I just can't seem to solve this problem: Integrate: (e^x)/(1+e^(3x)) dx I've tried substituting with : u = e^x, u = e^3x and u= 1+e^3x, but nothing seems to work out. Maybe i'm just missing something very obvious but I'm just lost at this point thanks in advance!