Question

Let A = {1, 2, 3, 4} and B = {x, y, z}. (a) List five functions from A to B. (b)How many functions f : A→B are there? (c) How many functions f : A→B are one-to-one? (d) How many functions g: B →A are there? (e) How many functions g: B →A are one-to-one? (f) How many functions f : A→B satisfy f (1) = x? (g) How many functions f : A→B satisfy f (1) = f (2)=_ x? (h) How many functions f : A→B satisfy f (1) = x and f (2) = y?

Answer 1

there should be thrms presented in your material that defines how to count these :)

Answer 2

also, how a function is defined; do we have to use all of A? and all of B?