let's recall that an inverse function has the same pair of coordinates as the original function, but backwards, or namely the inverse's range is the original's domain.
[tex]\bf \stackrel{f(x)}{\begin{array}{|cc|ll} \cline{1-2} 4&2\\ 6&3\\ 8&4\\ \cline{1-2} \end{array}}\qquad \qquad \stackrel{f^{-1}(x)}{\begin{array}{|cc|ll} \cline{1-2} 2&4\\ 3&6\\ 4&8\\ \cline{1-2} \end{array}}[/tex]
