# Matrix is too small, how to make it bigger?

I am trying to make the following matrix bigger since the elements do not fit quite well inside of it. I don't know why..

\documentclass[11pt,a4paper,oneside]{report} % KOMA-Script book
\usepackage[pdftex]{graphicx} % to work with PDFLaTex
\usepackage[T1]{fontenc}
\usepackage{fouriernc}
\usepackage{amsfonts,amsmath,amssymb,amsthm}
\usepackage[a4paper, hmargin={3.5cm,3cm}, vmargin={2.5cm,2.5cm}]{geometry} % margin
\usepackage{multicol}
\usepackage{chngcntr} % added to reset footnote for each chapter
\counterwithout{footnote}{chapter}%added to reste footnote for each chapter
\usepackage{fancyhdr}
\usepackage{enumerate}
%\counterwithout{equation}{chapter} % undo numbering system provided by phstyle.cls
\usepackage{wasysym} % symbols
\usepackage[hang]{footmisc} %to align text of footnotes

\begin{document}
Unscalled matrix
\begin{equation*}
\begin{bmatrix}
a_{1}&u_{2}&\frac{a_{1}}{d}u_{3}\\[6pt]
a_{2}&u_{1}&\frac{a_{2}}{d}u_{3}\\[6pt]
a_{3}&0&u_{4}\\[6pt]
\end{bmatrix}
\end{equation*}

and rescalled..a bit ugly..
\begin{equation*}
\scalebox{2.4}{\Bigg[}\begin{matrix}
a_{1}&u_{2}&\frac{a_{1}}{d}u_{3}\\[6pt]
a_{2}&u_{1}&\frac{a_{2}}{d}u_{3}\\[6pt]
a_{3}&0&u_{4}\\[6pt]
\end{matrix}
\scalebox{2.4}{\Bigg]}
\end{equation*}

also this one
\begin{equation*}
\begin{vmatrix}
1&z&x^2r+y^2t+z^2+2xys\\0&x&x^2b+y^2d+2zx\\0&y&x^2a+y^2c+2zy
\end{vmatrix}
\end{equation*}
\end{document}


and the output...

Thank you

-

You could change \arraystretch. I think the following both look fine:

\renewcommand\arraystretch{1.2}
\begin{equation*}
\begin{bmatrix}
a_{1}& u_{2}& \frac{a_{1}}{d}u_{3}\\
a_{2}& u_{1}& \frac{a_{2}}{d}u_{3}\\
a_{3}& 0& u_{4}
\end{bmatrix}
\begin{vmatrix}
1& z& x^2r+y^2t+z^2+2xys\\
0& x& x^2b+y^2d+2zx\\
0& y& x^2a+y^2c+2zy
\end{vmatrix}
\end{equation*}


Another possibility is \delimitershortfall=0pt This parameter tells TeX how much shorter than the height of the contents the braces are allowed to be. Normally, it is 5pt and so the braces are permitted to be shorter than the matrix contents by 5 points. It can be made negative to force the braces to be stictly taller than the contents.

A third possibility is to put a \strut on the first row or anything invisible but tall such as \rule{0pt}{12pt}.

-
Great job! This really works:) Thank you. –  user124471 Aug 14 '14 at 7:42

I'm not entirely sure I understand your objective. For now, I assume that by "bigger" you mean larger, i.e., "display-style" fractions.

Since you're already loading the amsmath package, I suggest you use \dfrac instead of \frac. To add extra vertical space, you might start with [2ex]; you're obviously free to change this to suit your preferences.

\documentclass[11pt,a4paper,oneside]{report}
\usepackage[T1]{fontenc}
\usepackage{fouriernc}
\usepackage{amsfonts,amsmath,amssymb,amsthm}
\usepackage[hmargin={3.5cm,3cm}, vmargin={2.5cm,2.5cm}]{geometry}

\begin{document}
Using \verb+\frac+ and default amount of vertical spacing:
\begin{equation*}
\begin{bmatrix}
a_{1}&u_{2}&\frac{a_{1}}{d}u_{3}\\
a_{2}&u_{1}&\frac{a_{2}}{d}u_{3}\\
a_{3}&0&u_{4}
\end{bmatrix}
\end{equation*}

Using \verb+\dfrac+ and some extra vertical spacing:
\begin{equation*}
\begin{bmatrix}
a_{1}&u_{2}&\dfrac{a_{1}}{d}u_{3}\\[2ex]
a_{2}&u_{1}&\dfrac{a_{2}}{d}u_{3}\\[2ex]
a_{3}&0&u_{4}
\end{bmatrix}
\end{equation*}

\end{document}

-
Well you see clearly that elements of the matrix do not fit inside of it. In both cases the element of the first row and the third column ''sticks out''. –  user124471 Aug 14 '14 at 7:39
@user124471 - thanks for providing this clarification. –  Mico Aug 14 '14 at 13:05