02_05_ex_51.tex

{$\ds f(x) = \sqrt[3]{x} + x^{2/3}$
}
{$\fp(x) = \frac13x^{-2/3}+\frac23x^{-1/3} = \frac1{3\sqrt[3]{x^2}}+\frac2{3\sqrt[3]{x}}$
}