[tex]\bf a^{\frac{{ n}}{{ m}}} \implies \sqrt[{ m}]{a^{ n}} \qquad \qquad
\sqrt[{ m}]{a^{ n}}\implies a^{\frac{{ n}}{{ m}}}\\\\
-------------------------------\\\\
4^{\frac{2}{3}}\implies \sqrt[3]{4^2}\implies \sqrt[3]{(2^2)^2}\implies \sqrt[3]{2^4}\implies \sqrt[3]{2^{3+1}}\implies \sqrt[3]{2^3\cdot 2}
\\\\\\
2\sqrt[3]{2}[/tex]