# Right-aligned columns using the tabularx environment

I'm trying to typeset a matrix which has entries of differing widths. However, for aesthetic reasons, I would like each of the columns of the matrix to be the same width, and I'd furthermore like them to be right-aligned.

I'm working in the tabularx environment (because of its ability to adjust column width uniformly). However, if I compile

\documentclass{amsart}
\usepackage{amsmath}
\usepackage{array}
\usepackage{tabularx}

\begin{document}

$\left[ \begin{tabularx}{1in}{XXX} x & 0 & y\\ 0 & y & -x \end{tabularx} \right]$

\end{document}


then the columns don't have the desired justification. I looked through the tabularx documentation and discovered that I should define a new column type. So I tried the following:

\documentclass{amsart}
\usepackage{amsmath}
\usepackage{array}
\usepackage{tabularx}

\begin{document}

\newcolumntype{R}{>{\raggedleft\arraybackslash}X}

$\left[ \begin{tabularx}{1in}{RRR} x & 0 & y\\ 0 & y & -x \end{tabularx} \right]$

\end{document}


This produced no change in output. What am I missing?

EDIT: The following code

\documentclass{amsart}
\usepackage{amsmath}
\usepackage{array}
\usepackage{tabularx}

\begin{document}

\newcolumntype{P}{>{\raggedleft\arraybackslash }p{.075in}}
\newcolumntype{Q}{>{\raggedleft\arraybackslash $}p{0.075in}<{$}}

$\left[\begin{array}{PPP} x & 0 & y\\ 0 & y & -x \end{array}\right]$
$\left[\begin{array}{QQQ} x & 0 & y\\ 0 & y & -x \end{array}\right]$

\end{document}


produces THIS output:

-

First, you are missing mathmode in your example. You need $/$ around the \left[/\right].

This produced no change in output. What am I missing?

On my machine it produces a change! The columns are right aligned.

The tabularx is not really meaningful if you use X for ALL columns. In this case just use p{<width>} columns with a normal tabular or array environment, e.g.:

  \newcolumntype{P}{>{\raggedleft\arraybackslash}p{.2in}}
\begin{array}{PPP}


On my installation this gives almost the same result as your second code with the R column:

The first can be fixed with \hbox{-x} and the second one with \!\!-x.