The function $r(t)=\sqrt[3]{t-2}$ is hauntingly close to $I(x),$ with one key difference. Whereas the expression for $I(x)$ includes an even indexed root $($namely square root$),$ the formula for $r(t)$ involves an odd indexed root $($the cube root$).$ Since odd roots of real numbers $($including negative real numbers$)$ are real numbers, there is no restriction on the inputs to $r.$ Hence, our domain is $(-,).$