# Series Converges

• April 28th 2012, 10:19 PM
JC05
Series Converges
$f(x) = \sum_{n=0}^{\infty}(-1)n\frac{x2n}{(2n)!}$

Let f be defined by the series for all x where the series converges
A. What is the domain
B. Is f odd, even or neither
C. Assuming that derivatives can be computed term by term show that f'' = f
• April 29th 2012, 04:55 AM
girdav
Re: Series Converges
A. Use ratio test.
B. What about the function $x\mapsto x^{2n}$?
C. What have you done?
• April 29th 2012, 10:36 AM
manhole
Re: Series Converges
You in Leache's class?

hahah

Anyway, for A domain should be infinity.
I haven't found an answer for B (could be neither)
and for C http://www.math.sunysb.edu/~disconzi...ging_index.pdf
• April 29th 2012, 03:42 PM
JC05
Re: Series Converges
AHHH HAHA
THANKS This problem is killing me....