5
$\begingroup$

This question already has an answer here:

I am trying to find what this value will converge to $$\sum_{n = 1}^{ \infty}\frac{n^2}{n!}$$

I tried using the Taylor series for $e^x$ but couldn’t figure out how to manipulate it to get the above expression, can someone help me out.

Edit: I have seen the solution, the manipulation required didn’t come to me, is there any resource that you guys can tell me about where I can find/practice more questions like this?

$\endgroup$

merged by quid Mar 11 at 14:04

This question was merged with What's the value of $\sum\limits_{k=1}^{\infty}\frac{k^2}{k!}$? because it is an exact duplicate of that question.