Yeah I had those forms and subbed it back into the d.eq
\displaystyle y''=\sum_{n=0}^{\infty}n(n-1)a_nx^{n-2} + \displaystyle y'=\sum_{n=0}^{\infty}na_nx^{n-1} + \displaystyle y=\sum_{n=0}^{\infty}a_nx^n = 0
then
\displaystyle y''=\sum_{n=0}^{\infty}(n+2)(n+1)a_nx^{n} + \displaystyle y'=\sum_{n=1}^{\infty}na_nx^{n} + \displaystyle y=\sum_{n=0}^{\infty}a_nx^n = 0
Right?
My equation becomes 2a_2 + a_0 = 0 then to a_2 = -(1/2) a_0
EDIT: Ah I dunno how to get the formula source code up :/
you need to wrap them in math tags
[tex] [ /math] no space between the bracket and forward slash. [ /
If you change your editor to advanced mode you can just click
Tex button in the upper right
I think this is what you typed, but you are missing the and in front of the function and the first derivative