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.

2) If R = infinity, does the series converge at only the x? For example...

lim n-> infinity of 24n/6 |X-4| would the interval be only 4 ?

3) This is the main problem ive been struggling on...

Suppose that the series of CnX^n converges when x=-4 and diverges when x=6. What can be said about the convergence or divergence of the following series?

a) Series (to infinity from n=0) of Cn,

b) Series of Cn8^n

c) Series of Cn(-3)^n

d) Series of ((-1)^n)Cn9^n

Any and all help is appreciated.