%%
%% The LaTeX Companion, 3ed
%%
%% Example 11-7-9 on page II-200 in "Ghostbusters\texttrademark ".
%%
%% Copyright (C) 2022 Frank Mittelbach
%%
%% It may be distributed and/or modified under the conditions
%% of the LaTeX Project Public License, either version 1.3c
%% of this license or (at your option) any later version.
%%
%% See https://www.latex-project.org/lppl.txt for details.
%%

\documentclass{tlc3examargin}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{111.0pt}

  \setlength\parindent{0pt}

%StartShownPreambleCommands
\usepackage{amsmath}
%StopShownPreambleCommands

\begin{document}
$\sqrt{x} + \sqrt{y}            + \sqrt{z}$ \\
$\sqrt{x} + \sqrt{\mathstrut y} + \sqrt{z}$ \\
$\sqrt{x} + \sqrt{\smash{y}}    + \sqrt{z}$ \\
$\sqrt{x} + \sqrt{\smash[b]{y}} + \sqrt{z}$
\end{document}