Define each of the following:
(i) injective function
(ii) surjective function
Give an example of each type of functions.

Solution:

(i) Injective function: It is, also known as one-one
function and is a type of function where every element in set A has an
image in set B.
Hence, f: A → B is one-one or injection function only if
has a unique solution .
For example: is injection for
f(x) = f(y)
⇒
⇒

(ii) Surjective function: It is, also known as onto
function and is a function where for every element of set A, there is
atleast one image in set B, such that no element in Set B is left
without a match or ordered pair.
For example: from the set of integers Z to the set of whole no. W is a surjective or onto function.