Possible Duplicate:
Nice-looking p-th roots
How can I move the root higher for this formula ? The fraction in the root is typeset to low:
\documentclass{minimal}
\begin{document}
$\sqrt[\frac{1}{3}]{\frac{4}{4.2}}$
\end{document}
the result of the document is


and
work? Is there any formula to calculate their arguments, depends on the fraction?
– lazyboy Aug 27 '12 at 13:27