This looks like the Taylor series for cos(x).Alright. We were just assigned this work and its due tomorrow. I got everything except these three problems, so help would be appreciated.

1) Find the radius of convergence and interval of convergence of the series:

((-1)^n)((X^2n)/(2n)!)

does this turn into lim as n->infinity of 2n/(2n+1) times |x^2| ?

The ! threw me off.

Compare to yours.