%% 
%%  An UIT Edition example
%% 
%%  Example 06-12-4 on page 109.
%% 
%%  Copyright (C) 2010 Herbert Voss
%% 
%%  It may be distributed and/or modified under the conditions
%%  of the LaTeX Project Public License, either version 1.3
%%  of this license or (at your option) any later version.
%% 
%%  See http://www.latex-project.org/lppl.txt for details.
%% 
%% 
%% ==== 
% Show page(s) 1
%% 
\documentclass[]{exaarticle}
\pagestyle{empty}
\setlength\textwidth{177.70511pt}
\AtBeginDocument{\setlength\parindent{0pt}}
\newcommand*\mathllap{\mathstrut\mathpalette\mathllapinternal}
\newcommand*\mathllapinternal[2]{\llap{$\mathsurround=0pt#1{#2}$}}
\newcommand*\clap[1]{\hbox to 0pt{\hss#1\hss}}
\newcommand*\mathclap{\mathpalette\mathclapinternal}
\newcommand*\mathclapinternal[2]{\clap{$\mathsurround=0pt#1{#2}$}}
\newcommand*\mathrlap{\mathpalette\mathrlapinternal}
\newcommand*\mathrlapinternal[2]{\rlap{$\mathsurround=0pt#1{#2}$}}
\StartShownPreambleCommands
\usepackage{amsmath}
\setlength\tabcolsep{0pt}
\StopShownPreambleCommands
\begin{document}
before the table
\begin{tabular}{|c|}\hline
Jana\\\rlap{Jana}\\\llap{Jana}\\[10pt]
$\mathclap{y=\sqrt{r^2-y^2}}$\\
$\mathllap{y=\sqrt{r^2-y^2}}$\\
$\mathrlap{y=\sqrt{r^2-y^2}}$\\\hline
\end{tabular}
after the table
\end{document}