a) $f(x) =\sqrt[3]{x + 2} -\sqrt[3]{x - 2}$
$TXD: D = \Bbb R$
Xét $f(-x) = \sqrt[3]{-x + 2} - \sqrt[3]{-x - 2}$
$= -\sqrt[3]{x - 2} + \sqrt[3]{x + 2} = f(x)$
Vậy $f(x)$ là hàm chẵn
b) $f(x) = \dfrac{x^2 +2}{\sqrt[3]{x^3 - x}}$
$TXD: D = \Bbb R \backslash\left\{-1;0;1\right\}$
Xét $f(-x) = \dfrac{(-x)^2 +2}{\sqrt[3]{(-x)^3 - (-x)}}$
$= \dfrac{x^2 +2}{\sqrt[3]{-x^3 +x}}$
$= \dfrac{x^2 +2}{\sqrt[3]{-(x^3 - x)}}$
$= -\dfrac{x^2 +2}{\sqrt[3]{x^3 - x}} = -f(x)$
Vậy $f(x)$ là hàm lẻ
