Find the number of all onto functions from the set {1, 2, 3, , n} to itself 5 Let A = {– 1, 0, 1, 2}, B = {– 4, – 2, 0, 2} and f, g : A → B be functions defined
by f (x) = x2 – x, x ∈ A and 
1
( )
2
1,
2
g x
x
=
−
−
 x ∈ A