1. The problem statement, all variables and given/known data Show that f(x) = x/(1+x^2) is continuous on R 2. Relevant equations f is continuous at a if for any epsilon > 0, there exists a number delta > 0 such that if |x-a|<delta, then |f(x)-f(a)|<epsilon. 3. The attempt at a solution |f(x) - f(a)| = |x/(1+x^2) - a/(1+a^2)| = |(x-a)(1-ax)/[(1+x^2)(1+a^2)]| If I can show that the previous is <= |(x-a)(1-ax)/(1-ax)| then I can cancel the (1-ax) and I'll be done right? I'm not even really sure if I started on this the right way, so any help would be appreciated.