Let f:{1,2,3}→{a,b,c,d} be defined by f(1)=a,f(2)=b,f(3)=c.
a. (i) Define an injective function and a surjective function.
b. (ii) Determine whether the given function f is injective. Give a reason for your answer.
c. (iii) Determine whether f is surjective. Give a reason for your answer.
d. (iv) Is f invertible? Justify your conclusion based on your answers to parts (ii) and (iii).