Function for which the dependent and independent variables that define the relationship between the domain and the image can be interchanged so that the new relationship obtained is also a function.
In other words, a function is invertible if its reciprocal is also is a function.
Example
The function f defined by the relation y = 3x − 2 is invertible.
By interchanging the variables x and y, the relation becomes x = 3y − 2 or y = \(\dfrac{(x + 2)}{3}\).
The relation g defined by y = \(\dfrac{(x + 2)}{3}\) is a function.