Inverse function $f$ is reverse function, denote as $f^{-1}$. If a function $f$ is mapping x to y, then $f^{-1}$ is mapping y to x,

To find the invers function of $y=f(x)$, we need to determine $x=f(y)$.

A function has an inverse if the function is a one-one function. One-one function is there is only one value of element of domain that mapped to one value of range, and vice versa.

Domain of $f^{-1}$ is same with range of $f$

Range of $f^{-1}$ is same with domain of $f$