P1-3: Xor y Each of the following differential equations has an integrating factor depending on only one variable. Find the integrating factor and solve the equation. (a) (4y x2) da + a dy = 0 (b) (2xy2 y) da + (2x x2y) dy = 0 (c) 2 da + (2x- 3y- 3) dy = 0; y(2) = 0 (d) (2y sin x + 3y4 sin x cos x) dx - (4y3 cos2 x + cos ) dy = 0