ok, so i have to integrate (e^x-e^-x)/(e^x+e^-x). any ideas on how to solve this problem?
Your (E^x-E^(-x))/(E^x+E^(-x)) equals Tanh[x]. And its integral is Ln[Cosh[x]]. Please visit one of most powerful math engines:
http://integrals.wolfram.com/index.jsp
All the best. Marek.