Math & Science ⇒ Elements within the matrix are of small size

[NELLLY]

Hi
I have the following matrix

Code: Select all

\[ P^{(t)}=P^t
=\bordermatrix[{[]}]{ \displaystyle
 &1&2\cr
1&\frac{b+(1-a)(a-b)^t}{1-a+b}&\frac{(1-a)-(1-a)(a-b)^t}{1-a+b}\cr
2&\frac{b-b(a-b)^t}{1-a+b}&\frac{(1-a)+b(a-b)^t}{1-a+b}}\label{Pt}\]

The problem is that the elements within the matrix are of small size. I used \diplaystyle but the problem still remain. What can I do?

[gmedina]

Hi,

use \dfrac instead of \frac, as the following example suggests:

Code: Select all

\documentclass[11pt,a4paper]{book}
\usepackage{amsmath}

\makeatletter
\newif\if@borderstar
   \def\bordermatrix{\@ifnextchar*{%
       \@borderstartrue\@bordermatrix@i}{\@borderstarfalse\@bordermatrix@i*}%
   }
   \def\@bordermatrix@i*{\@ifnextchar[{\@bordermatrix@ii}{\@bordermatrix@ii[()]}}
   \def\@bordermatrix@ii[#1]#2{%
   \begingroup
     \m@th\@tempdima8.75\p@\setbox\z@\vbox{%
       \def\cr{\crcr\noalign{\kern 2\p@\global\let\cr\endline }}%
       \ialign {$##$\hfil\kern 2\p@\kern\@tempdima & \thinspace %
       \hfil $##$\hfil && \quad\hfil $##$\hfil\crcr\omit\strut %
       \hfil\crcr\noalign{\kern -\baselineskip}#2\crcr\omit %
       \strut\cr}}%
     \setbox\tw@\vbox{\unvcopy\z@\global\setbox\@ne\lastbox}%
     \setbox\tw@\hbox{\unhbox\@ne\unskip\global\setbox\@ne\lastbox}%
     \setbox\tw@\hbox{%
       $\kern\wd\@ne\kern -\@tempdima\left\@firstoftwo#1%
         \if@borderstar\kern2pt\else\kern -\wd\@ne\fi%
       \global\setbox\@ne\vbox{\box\@ne\if@borderstar\else\kern 2\p@\fi}%
       \vcenter{\if@borderstar\else\kern -\ht\@ne\fi%
         \unvbox\z@\kern-\if@borderstar2\fi\baselineskip}%
         \if@borderstar\kern-2\@tempdima\kern2\p@\else\,\fi\right\@secondoftwo#1 $%
     }\null \;\vbox{\kern\ht\@ne\box\tw@}%
   \endgroup
   }
\makeatother

\begin{document}

\begin{equation}\label{Pt}
  P^{(t)} = P^t = 
  \bordermatrix[{[]}]{ 
    &1&2\cr
    1&\dfrac{b+(1-a)(a-b)^t}{1-a+b}&\dfrac{(1-a)-(1-a)(a-b)^t}{1-a+b}\cr
    2&\dfrac{b-b(a-b)^t}{1-a+b}&\dfrac{(1-a)+b(a-b)^t}{1-a+b}}
\end{equation}

\end{document}

Remarks: 1) Please provide complete, minimal code in your posts.
2) It seems that you want to cross-reference the posted formula; if this is so, change \[...\] to \begin{equation}...\end{equation} (as I did in my example); the explanation is simple: \[...\] doesn't produce any numbering, so using \label inside \[...\] will pick the wrong string to produce the reference.

[NELLLY]

Thanks gmedina. I will do it better next times.