Contoh 1.2.12.
Kadang-kadang berlaku \(f \circ g= g \circ f\text{.}\) Misalkan \(f(x) = x^3\) dan \(g(x) = \sqrt[3]{x}\text{.}\) Maka
\begin{equation*}
(f \circ g )(x) = f(g(x)) = f( \sqrt[3]{x}\, ) = (\sqrt[3]{x}\, )^3 = x
\end{equation*}
dan
\begin{equation*}
(g \circ f )(x) = g(f(x)) = g( x^3) = \sqrt[3]{ x^3} = x\text{.}
\end{equation*}