How can a graphing utility such as a graphing calculator be used to visually determine if two functions are inverses of each other?
We can graph $y=x$y=x on the same axes as the graphs of the two functions and look to see if the graphs intersect on the line $y=x$y=x.
If they do intersect on $y=x$y=x, then they are inverses. If they don't, they are not inverses.
We can graph $y=x$y=x on the same axes as the graphs of the two functions and look to see one of the graphs is a reflection of the other about $y=x$y=x.
If they are reflections, then they are inverses. If they aren't reflections, they are not inverses.
We look to see if the graphs are reflections of each other about the $y$y-axis.
If they are, they are inverses.
Examine the following graph containing two lines: