Functions

A function is a relation which is everywhere defined and not one-many.

Inverse

For a function to have its inverse relation be also a function:

• is onto
• is not many-one (in other words, must be one-one)

The above statement is true for all unrestricted function that has an inverse :

Real-valued functions

When both domain and codomains of a function are subsets of , the function is said to be a real-valued function.

Odd and Even functions

Odd function

A function that is .

Even function

A function that is .