Hello,

Im trying to arrange

$\displaystyle J_0(x) + \sum^{infnty}_{n=1} J_n(x) (r^n+{(-1)}^nr^{-n})$

into a power series.

I've attempted but cannot get it into the form required. I've tried subbing in the series representation of J_n(x) into it.

Any advice would be very helpful. Thanks