Given A = {2, 3, 4}, B = {2, 5, 6, 7}. Construct an example of each of the following:

a mapping from A to B which is not injective

TIP: – One – One Function: – A function is said to be a one – one functions or an injection if different elements of A have different images in B.


So, is One – One function


⇔ a≠b


⇒ f(a)≠f(b) for all


⇔ f(a) = f(b)


⇒ a = b for all


Now, f : A → B, denotes a mapping such that


f = {(2,2),(3,5),(4,5)}


Hence this is not injective mapping


21