\documentclass[12pt,dvips,landscape]{article}
% use latex; dvips; ps2pdf to process
\usepackage{pstricks-add}
\usepackage{geometry}
\topmargin-.75in\textheight7in
\oddsidemargin-.5in\textwidth10.5in
\pagestyle{empty}
\begin{document}
\begin{center}
\Huge\sf Graphs of the sine and cosine function in radians\\[30pt]
\end{center}

\bigskip

\psset{algebraic, VarStep=true, xAxisLabel=$x$, yAxisLabel=$y$, plotpoints=101, bordercolor=yellow}%, showpoints=true}
\Large
\begin{center}
\begin{psgraph}{->}(0,0)(-6.5, -1.5)(6.5,1.5){10in}{!}
\psplot[linecolor=red, border=2pt]{-6.5}{6.5}{sin(x)}
\multido{\n=0+1.57}{4}{\psplotTangent[linecolor=blue, arrows=<->]{\n}{.85}{sin(x)}}
\uput[d](1.57,0){$\frac{\pi}{2}$}
\psline(1.57,0)(1.57,1)
\uput[u](3.14,0){$\pi$}
\psline(4.71,-.5)(4.71,-1)
\psline(4.71,0)(4.71,-.075)
\uput[d](4.71,0){$\frac{3\pi}{2}$}
\uput[u](6.28,0){$2\pi$}
\end{psgraph}
\end{center}

\bigskip

\begin{center}
\begin{psgraph}{->}(0,0)(-6.5, -1.5)(6.5,1.5){10in}{!}
\psplot[linecolor=red, border=2pt]{-6.5}{6.5}{cos(x)}
\end{psgraph}
\end{center}

\bigskip

\begin{center}\tiny 
Graphs of sine (showing tangent lines) and cosine in radians and with equal units on the axes --- 
Math Poster 2007 --- 
%Peter Jipsen --- Chapman University --- 
math.chapman.edu
\end{center}
\end{document}