1. The problem statement, all variables and given/known data i need to solve this diff equation. y' = x2 + y2 y = 1 when x = 0 i can assume that the answer is a power series on the form Ʃanxn andi only need the 4 first non zero terms of the power-series answer 2. Relevant equations Ʃanxn 3. The attempt at a solution y = Ʃanxn y' = Ʃnanx(n-1) Ʃn*anx(n-1) - (Ʃanxn)2 = x2 i guess since the answer is only 4 first non zero term. i can write out the summation to 4 terms. if i do that im stuck with a bunch of a1 a2 a3 .... and i cant mange to find the value of those coefficients. and i dont really know if that is the right way of doing it at all.