P4, 50pts, method of multiple scales. Find a first-term expansion of the solutions of the following problems that is valid for large t. Hint: for (a), you might like to use complex exponentials; see the written notes from class. (a, 20pts) y" + €(y')³ + y = 0 for t > 0 and y(0) = 0, y'(0) = 1 = (b, 30pts) ey" + y + y = 0 for t > 0 and y(0) = 0, y(0) 1 Note: something very special happens here. The payoff is huge and I hope you'll try it!