# What is the domain of f(x) = (4x/3)((x^2 - 1)^(-1/3))?

It should be ${x}^{2} - 1 > 0 \implies \left(x - 1\right) \left(x + 1\right) > 0$ hence the range is
$\left(- \infty , - 1\right) U \left(1 , + \infty\right)$