1. The problem statement, all variables and given/known data Find the interval of convergence of the infinite series: ∞ ∑ (x-1)n / 2n n = 1 2. Relevant equations Using the ration test. It converges if the absolute value of the limit of f(n+1)/f(n) as n -> ∞ < 1. Well, I hope that's how you write it. I'm sure you guys know how to use the ration test. 3. The attempt at a solution I actually believe I have the answer. But I have no way of knowing if it is right. Here is my answer: The interval of convergence is -1 < x < 3. I got this by using the ratio test, and then eliminating factors of (x-1)n and 2n (after expanding the exponents), leaving me with the limit of lim (x-1)/2 as n -> ∞ Then, since there is no n, then that limit IS (x -1)/2 (unless I'm totally off) And the absolute value of that has to be less than 1 for it to converge, so -1 < (x-1)/2 < 1 -2 < x - 1 < 2 -1 < x < 3 Is this correct? Do you need me to post the part where I canceled out terms before I took the limit? Thanks!