1. The problem statement, all variables and given/known data Find the limit of f(x)=[xcosx]/[x^3 + 1] as x tends to infinity. 2. Relevant equations 3. The attempt at a solution Can i use l'hopitals rule here? Or if not, what are the conditions for f(x) to meet so that i may use l'hopitals rule? Without using l'hop i know that cosx would oscillate between -1 and 1 and that is multiplied by infinity. Then the denominator would tend towards infinity. So what is infinity over infinity?