1. The problem statement, all variables and given/known data I have to find the radius of convergence and convergence interval. So for what x's the series converge. The answer is supposed to be for every real number. So the interval is: (-∞, ∞). So that must mean that the limit L = 0. So the radius of convergence [ which is given by R = 1/L ] is going to be ∞. 2. Relevant equations (?) 3. The attempt at a solution I tried using with an = but i don't seem to get anywhere.... Is there another way of showing that the lim = 0 ?