## What is function and type of Functions

What is function? Function (mathematics) is defined as if each element of set A is connected with the elements of set B, it is not compulsory that all elements of set B are connected; we call this relation as function.

f: A → B ( f is a function from A to B )

Types of function:

1. One-one Function or Injective Function : If each elements of set A is connected with different elements of set B, then we call this function as One-one function.
2. Many-one Function : If any two or more elements of set A are connected with a single element of set B, then we call this function as Many one function.
3. Onto function or Surjective function : Function f from set A to set B is onto function if each element of set B is connected with set of A elements.
4. Into Function : Function f from set A to set B is Into function if at least set B has a element which is not connected with any of the element of set A.
5. One-one Onto Function or Bijective function : Function f from set A to set  B is One one Onto function if(a)   f is  One one function(b)   f is Onto function.