Compute approximation to the solution of the equation $y+\epsilon \sin y=x^2$
using perturbation method. 
Assume that terms involving powers of $\epsilon$ of order 3 or more can be ignored. 

So far I only have:
$$(y\_0 +\epsilon y\_1 +\epsilon ^2 y\_2 +...) + \epsilon \sin(y\_0 +\epsilon y\_1 +\epsilon ^2 y\_2 +...)$$

Any help appreciated!