The Identity Function
Another easy but important instance of a function is a function which sends every element of the domain to itself.
Consider X by any non-empty set, & f be the function of X denoted by setting f (x) = x, for all x ∈ X.
This function is called as the identity function on X and is indicated by IX.
The graph of IR, the identity function of R, is described in given Figure. this is the line y = x.
