I need some quick help on problem 37 from the practice test:
What is the sum of k^2/k! as k = 0 -> infinity?
The booklet claims the answer is 2*e, and I know for a fact that the sum of 1/k! is e, but I can't logically get from one to the other. I've tried looking at Taylor series, but it's no use. Any help would be greatly appreciated.