# size and location of cube root symbol [duplicate]

Possible Duplicate:
Nice-looking p-th roots

On math.stackexchange I wanted the cube root of a fraction in display mode, and used $$\sqrt[3]{\frac ab}$$ to get it. The 3 comes out very small and low in the root sign. I also thought of $$^3\sqrt{\frac ab}$$ but the 3 comes out too far to the left.

## marked as duplicate by Peter Grill, percusse, lockstep, Martin Schröder, Marco DanielAug 16 '12 at 14:14

You can use \leftroot (for horizontal shifting), and/or \uproot (for vertical shifting) from the amsmath package; using \scriptstyle you can increase the size of the index (not sure if this is a good idea); preferable to use a superscript instead of the root:
\documentclass{article}
$\sqrt[3]{\frac{a}{b}}\qquad \sqrt[\leftroot{-1}\uproot{2}\scriptstyle 3]{\frac{a}{b}}\qquad \Bigl(\frac{a}{b}\Bigr)^{1/3}$