# Alignment and phantom

by Thales   Last Updated November 09, 2018 00:23 AM - source

The MWE shows in the result the alignment as I need it in the first step. My questions are:

1. Now after the "1" there should appear again a "4", exactly beneath the "4" of the very first line. How can I do this?
2. Is there a more elegant solution in general (so that question 1 can be solved more easily)?

\documentclass{article}
\usepackage{amsmath}
\begin{document}
\begin{equation*}
\begin{aligned}
&&\sqrt{05\;47\;56} = 2 \\
&-&4\phantom{\sqrt{05\;47\;56}} \\
&&\rule{1cm}{0.4pt} \phantom{\sqrt{05\;47}} \\
&&1\phantom{\sqrt{05\;47\;56}}
\end{aligned}
\end{equation*}
\end{document}

Tags :

You can use \mathmakebox and array. In the first column, the radical is placed as if it had the width of the radical sign (and no vinculum).

\documentclass{article}
\usepackage{amsmath,mathtools,calc}

\begin{document}

\begin{equation*}
\setlength{\arraycolsep}{0pt}
\begin{array}{r r @{\;} r @{\;} r l}
\mathmakebox[\widthof{$\sqrt{\vphantom{0}}$}][l]{\sqrt{\phantom{05\;47\;56}}} &
05 & 47 & 56 & {} = 2 \\
-&   4 \\
\cline{2-2}
&   1
\end{array}
\end{equation*}

\end{document}


egreg
November 08, 2018 23:59 PM

\documentclass{article}
\usepackage{mathtools}

\begin{document}

\begin{align*}
\sqrt{05\;47\;56} & = 2 \\
-\enspace 4\phantom{\;47\;56} & \\[-3ex]
\rule{1.1cm}{0.4pt} \phantom{\;56} & \\[-1.5ex]
1\mathrlap{\;4}\phantom{\;47\;56} &
\end{align*}

\end{document}


Bernard
November 09, 2018 00:17 AM