MATLAB code

\documentclass{article}
\usepackage{listings}
\lstset{language=Matlab, basicstyle=\ttfamily\small, frame=single}
\begin{document}
\section*{MATLAB in LaTeX}

A MATLAB listing, typeset with \texttt{listings} (the \texttt{matlab-prettifier} package gives a closer MATLAB look
in a full LaTeX run).

\emph{In this preview:} the code is shown, not run. To compute with it, open a notebook in MATLAB mode (File,
New, Notebook, then choose MATLAB) and paste it there; then copy the results back.

\begin{lstlisting}
% the eigenvalues of a symmetric matrix
A = [2 -1 0; -1 2 -1; 0 -1 2];
[V, D] = eig(A);
lambda = diag(D)'
x = linspace(0, 2*pi, 100);
plot(x, sin(x)), grid on
\end{lstlisting}

For this $A$, the eigenvalues are $2 - \sqrt{2}$, $2$ and $2 + \sqrt{2}$:
\[
  A = \begin{pmatrix} 2 & -1 & 0 \\ -1 & 2 & -1 \\ 0 & -1 & 2 \end{pmatrix},
  \qquad \lambda \in \{\, 2-\sqrt{2},\ 2,\ 2+\sqrt{2} \,\}.
\]
\end{document}