I In differentlal förm M dã + N dy = 0. ne equation (3x°y+ 6 cos(3a) y ?) dæ + (3x - 4y ?)dy = 0 e differential form M dx + N dy 0 is not exact. Indeed, we have M-N, For this exercise we can find an integrating factor which is a function of y alone since My-N M is a function of y alone. Namely we have µ(y) Multiplying the original equation by the integrating factor we obtain a new equation M da + N dy = 0 where %3D M %3D N = Which is exact since M, N = are equal.