- Consider the differential equation 2xy dy [1 + (1 + y + (2 + y) dr x - y (a) Show by hand calculation that this equation is exact, using the test given in class. (b) Use the method given in class to determine, by hand, a potential function p(x, y) such that do x = 0. dx x - y do 2xy (x + y) (x + y) and write down an implicit formula for the general solution of the differential equation (1) using this function. Hint: it is easier to integrate do/ay partially in y. - (1) 1 +