Power Series/Differential Equations

Find the first four nonzero terms in each of two linearly independent power series solutions about the origin.

What do you expect the radius of convergence to be for each solution?

$\displaystyle (cosx)y^{''} +xy^{'} -2y=0 $

**Set the coefficients near zero and first terms to 1**

I am not exactly sure what the bolded sentence means. Also, how should I go about starting the problem? Is it best to start writing out the series for each term? like

Cosx = $\displaystyle 1-\frac{x^2}{2!} + \frac{x^4}{4!} + ... $

and so on.

Thanks for any help!