What is/are the classification of functions that has its inverse?

Invertible functions

Step-by-step explanation:

An inverse of a function is one that reverses the operation of the function such that the result of the function on a variable, is reversed back to the initial variable

Therefore, when we have the the result of the function, f on x as y given as follows;

f(x) = y

The inverse of the function, g on the result, y gives the initial variable, x as follows;

g(y) = x

Example of invertible functions includes;

f(x) = x²

An example of a non-invertible function includes;

f(x) = 2·x².