# Typesetting an empty square root

Is there a preferred way to typeset an empty sqrt? What I'm doing now is \sqrt{\phantom{a}}, are there other/preferred ways like a standalone symbol? Or should I just create a new macro with the phantom a?

• I'd just use \surd unless you specifically need the top bar. Dec 15, 2013 at 13:27
• I didn't know about \surd When the sqrt is introduced in mathematical textbooks, how is the empty symbol printed? Is it ok to print it without the top bar? Dec 15, 2013 at 13:30
• Where the Chicago Manual of Style writes "The radical sign √ is used to denote the square root" I would type that in LaTeX as The radical sign $\surd$ is used to denote the square root. Dec 15, 2013 at 13:47
• @NicolaTalbot Ok, thanks, I'll check if it is also used in the local textbooks and if yes I'll follow your advice. Dec 15, 2013 at 13:50

The \surd command just produces the radical symbol √ as opposed to \sqrt{stuff} which typesets the square root of stuff with a bar over stuff. The Chicago Manual of Style uses just the radical symbol in the text "The radical sign √ is used to denote the square root".

\documentclass{article}

\begin{document}
Compare:

\begin{itemize}
\item The radical sign $\surd$ is used to denote the square root.

\item The radical sign $\sqrt{}$ is used to denote the square root.

\item The radical sign $\sqrt{\phantom{x}}$ is used to denote the square root.
\end{itemize}

Alternatively: the square root of $x$ is denoted $\surd x$ or $\sqrt{x}$.

\end{document}


The Penguin Dictionary of Mathematics also just uses the radical sign (without an over bar) when defining both the terms "radical" and "square root".

• Notice that \surd places the symbol a bit higher, hence producing more pleasant vertically centered output.
– yo'
Dec 15, 2013 at 17:51
• Let me add that the bar used in root notation historically was used as parentheses, before parentheses were introduced. So it is correct to write √(2 + 2) = 2. Jul 24, 2022 at 17:18