An inverse relation is a relation that interchanges the input and output values of a specific relation. In other words, it is the relation that undoes a certain relation. Consider the mapping diagram that shows a relation $p$ that takes elements from set $A$ and returns elements from set $B.$ The relation that undoes $p$ is $q.$ In this case, $q$ takes elements from set $B$ and returns elements from set $A.$ Relations can also be represented by a collection of ordered pairs. Here, the inverse of a relation is obtained by interchanging the elements of the ordered pairs of the original relation. Graphically, the inverse of a relation is a reflection across the line $y=x.$ If the inverse relation of a function is also a function, then it is called an inverse function.