3. (20 points) Exactness of first-order equations. For the following, assume that f(y), g(z), h(y) # 0 for all real = and y. (a) Show that every first-order autonomous differential equation of the form Y = f(y) is exact. (b) Show that every separable differential equation of the form y' = g(z)h(y) is exact. (c) Draw a Venn diagram to visually represent the relationships between the following classes of differential equations: exact, separable, and first-order autonomous. Show clearly the areas of overlap and exclusivity between these categories