Explanation:
Let f be a function having domain in the set X, and range in the set Y. Then f would be invertible if there exists a function g having domain Y and range X, such as:
![{\displaystyle f(x)=y\,\,\Leftrightarrow \,\,g(y)=x](https://img.qammunity.org/2021/formulas/mathematics/middle-school/eays9i1gp221q35w3lfbofyp82v3c979ra.png)
In other words, the function
is applied to an input x, and gives an outcome of y, then its inverse function, let say
, can be applied to y to give the result of x.
In other words,
y = f(x) if and only if x = g(y)
For example, considering the function
![\:\:f\left(x\right)=b\:-x](https://img.qammunity.org/2021/formulas/mathematics/middle-school/5rzqc2w97w71nehi9oc6n29er54ghrck22.png)
the inverse is:
![f^(-1)\left(y\right)=b\:-y](https://img.qammunity.org/2021/formulas/mathematics/middle-school/u2uyi8h2a5x13m5vl0ud1t9jjtdzk3qsd7.png)