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* = 3*x* − 2 is invertible.

By interchanging the variables *x* and *y*, the relation becomes *x* = 3*y* − 2 or *y* = \(\dfrac{(x + 2)}{3}\).

The relation *g* defined by *y* = \(\dfrac{(x + 2)}{3}\) is a function.