remember
[tex](x^m)^n=x^{mn}[/tex]
and
[tex] \sqrt[n]{x} =x^ \frac{1}{n} [/tex]
and
[tex]x^{m+n}=(x^m)(x^n)[/tex]
so
[tex]( \sqrt[3]{ \sqrt{x} } )^4[/tex]=
[tex]( \sqrt[3]{ x^ \frac{1}{2} } )^4[/tex]=
[tex]((x^ \frac{1}{2})^ \frac{1}{3} )^4[/tex]=
[tex](x^ \frac{1}{6})^4 [/tex]=
[tex]x^ \frac{4}{6} [/tex]=
[tex]x^ \frac{2}{3} [/tex]=
[tex] \sqrt[3]{x^2} [/tex]
