1. The problem statement, all variables and given/known data Without a graphing calculator, how can you tell that the function f(x) = x/(x^2+1) is one-to-one? 2. Relevant equations 3. The attempt at a solution You can sketch both x and 1/(x^2+1) separately but I did not think it was obvious that when you multiplied them togethor the result was not one-to-one.