# Big matrix in latex

I have a big matrix which exceeds the width of page, how can I fix this problem?

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You can use the nccmathpackage, an extension to amsmath that defines medium-sized mathematics, intermediate between textstyle and displaystyle (ca 80 % of the displaystyle size). With a suitable text width, it's OK but, of course, everything depends on what you actually have. Here is an illustration with textwidth=16cm and both styles:

    \documentclass{article}

\usepackage[showframe, nomarginpar, textwidth = 16cm]{geometry}
\usepackage{amsmath}
\usepackage{nccmath}
\newenvironment{mpmatrix}{\begin{medsize}\begin{pmatrix}}%
{\end{pmatrix}\end{medsize}}%

\begin{document}

$\begin{mpmatrix} a+b+c+d+e+f+g+h+i+j+k+l+m+n+o & a+b+c+d+e+f+g+h+i+j+k+l+m+n+o \\ a+b+c+d+e+f+g+h+i+j+k+l+m+n+o &a+b+c+d+e+f+g+h+i+j+k+l+m+n+o \end{mpmatrix},$
$\begin{pmatrix} a+b+c+d+e+f+g+h+i+j+k+l+m+n+o & a+b+c+d+e+f+g+h+i+j+k+l+m+n+o \\ a+b+c+d+e+f+g+h+i+j+k+l+m+n+o &a+b+c+d+e+f+g+h+i+j+k+l+m+n+o \end{pmatrix},$

\end{document}


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@rose: Before you start using nccmath too much in your code I thought I'd refer you to: Is there a replacement for nccmath?. I was using nccmath for a while but then abandoned it due to the problems listed in that question. –  Peter Grill Mar 19 '14 at 4:43

Using smallmatrix:

\documentclass{article}
\usepackage{amsmath}

\begin{document}
\noindent X \hrulefill X
$\begin{smallmatrix} a+b+c+d+e+f+g+h+i+j+k+l+m+n+o & a+b+c+d+e+f+g+h+i+j+k+l+m+n+o \\ a+b+c+d+e+f+g+h+i+j+k+l+m+n+o &a+b+c+d+e+f+g+h+i+j+k+l+m+n+o \end{smallmatrix}$
\noindent X\hrulefill X

\end{document}


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In those cases, I'd suggest you to use some names for the entries and then explain those names in the text, as the following example illustrates:

\documentclass{article}
\usepackage{amsmath}

\begin{document}

$\begin{pmatrix} \alpha & \beta \\ \gamma & \delta \end{pmatrix},$
where $\alpha=a+b+c+d+e+f+g+h+i+j+k+l+m+n+o$, $\beta=a+b+c+d+e+f+g+h+i+j+k+l+m+n+o$, $\gamma=a+b+c+d+e+f+g+h+i+j+k+l+m+n+o$
and $\delta=a+b+c+d+e+f+g+h+i+j+k+l+m+n+o$.

\end{document}


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Or use of array in an math environment

Code

\documentclass[12pt]{article}
\usepackage{amsmath}
\thispagestyle{empty}
\begin{document}
$\left ( \begin{array}{ccc} \begin{array}{l} a+b+c+d+e+f+g+h\\ +i+j+k+l+m+n+o \end{array} & \cdots & \begin{array}{l} a+b+c+d+e+f+g+h\\ +i+j+k+l+m+n+o \end{array} \\ \vdots & \ddots & \vdots\\ \begin{array}{l} a+b+c+d+e+f+g+h\\ +i+j+k+l+m+n+o \end{array} & \cdots & \begin{array}{l} a+b+c+d+e+f+g+h\\ +i+j+k+l+m+n+o \\ \end{array} \end{array} \right )$

\end{document}

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