Answer to Question #274404 in Math for Leyahhhh

Question

Let f : A → B, g : B → C, and h : C → D be functions.

1. State what you need to show to conclude that h ◦ (g ◦ f) = (h ◦ g) ◦ f. 13

2. Consider now some a ∈ A. Calculate h((g ◦ f)(a)) and (h ◦ g)(f(a)). Are they equal?

3. Use your solutions to (1)–(2) to conclude that h ◦ (g ◦ f) = (h ◦ g) ◦ f.