Radius and interval of convergence
Hi, I'm trying to do this question, but I'm stuck.
Find the radius and interval of convergence of the series:
The summation from 2 to inifinity.
I applied the ratio test and got that the limit equals abs(1/x^2). Applying the inequality I got abs(1/x^2) < 1.
I'm stuck here, because shouldn't the radius of convergence be 1? According to the inequality, the series will converge on two intervals: [-inf, -1) and (1, inf].
Some help would be greatly appreciated.