Thread: Discrete maths

hey guys this is the question where im stuck please help !

i) Let A = {a, b, c, d} and B = {1, 2, 3}. Determine whether the relations R from A to B are functions. If so, in each case, give its range and check whether it is onto & one-to-one:
a) R = {(a, 1), (b, 2), (a, 2), (c, 1), (d, 3)} (5 Marks)
b) R = {(a, 1), (b, 1), (c, 1), (d, 1)} (7Marks)

A relation from A to B is a function if and only if its domain is all of A and no two pairs have the same first term.