Question

Identify injective surjective bijective functions

Answer 1

Injective means that every member of "A" has its own unique matching member in "B".

As it is also a function one-to-many is not OK

And we won't have two "A"s pointing to the same "B", so many-to-one is NOT OK.

But we can have a "B" without a matching "A"

Injective functions can be reversed!

If "A" goes to a unique "B" then given that "B" value we can go back again to "A" (this does not work when two or more "A"s pointed to one "B" like in the "General Function")

Read Inverse Functions for more.

Injective is also called "One-to-One"

 

Surjective means that every "B" has at least one matching "A" (maybe more than one).

There won't be a "B" left out.

 

Bijective means both Injective and Surjective together.

So there is a perfect "one-to-one correspondence" between the members of the sets.

(But don't get that confused with the term "One-to-One" used to mean injective).

Hopes it help
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Answer 2

Answer:

=> A function f: A---->B is said to be ( one - one ) or injective .

If different elements of A are associated with different elements of B that is if a1, a2 belongs to A and a1 is not equals to a2.

=> A function f :A--> B,is said to be onto or subjective ,

If the range of f is B that is if for each B belongs to B , there is an a belongs to A such that f (a) is equals to b .

=> Bijection

If a function is both one one and onto it is called bijective.

Hope this helps you