<?xml version="1.0" encoding="UTF-8"?>

<record version="3" id="7076">
 <title>polar curve</title>
 <name>PolarCurve</name>
 <created>2005-05-18 17:52:46</created>
 <modified>2005-05-20 11:55:44</modified>
 <type>Example</type>
<parent id="7073">famous curves</parent>
 <creator id="3771" name="CWoo"/>
 <author id="3771" name="CWoo"/>
 <classification>
	<category scheme="msc" code="53A04"/>
	<category scheme="msc" code="51-01"/>
 </classification>
 <defines>
	<concept>lemniscate</concept>
	<concept>rhodonea</concept>
	<concept>cardioid</concept>
	<concept>limacon</concept>
 </defines>
 <synonyms>
	<synonym concept="polar curve" alias="lima\c{c}on"/>
 </synonyms>
 <related>
	<object name="AreaOfPlaneRegion"/>
	<object name="CassiniOval"/>
 </related>
 <preamble>\usepackage{amssymb,amscd}
\usepackage{amsmath}
\usepackage{amsfonts}

% used for TeXing text within eps files
%\usepackage{psfrag}
% need this for including graphics (\includegraphics)
\usepackage{graphicx}
% for neatly defining theorems and propositions
%\usepackage{amsthm}
% making logically defined graphics
%\usepackage{xypic}

% define commands here</preamble>
 <content>Polar curves are plane curves in $\mathbb{R}^2$ that are expressed in polar coordinates $(r,\theta)$.  The two simplest polar curves are obtained when one of the two coordinates is set to be a constant.  If the first coordinate is set to a constant $r$, we have a circle with radius $\lvert r \rvert$, or a point when $r=0$.  When the second coordinate is the constant instead, say $c$, we have a straight line through the (polar) origin, with slope = $\tan c$.


\begin{center}
\includegraphics{polar_curve_1.eps}
\hspace{1in}
\includegraphics{polar_curve_2.eps}
\end{center}

Using polar coordinates, one can generate many visually pleasing
curves.  Below are some of the most popular ones.

\begin{center}
\includegraphics{polar_curve_3.eps}
\end{center}
\vspace{10pt}
\begin{center}
\includegraphics{polar_curve_4.eps}
\hspace{1in}
\includegraphics{polar_curve_5.eps}
\end{center}
\vspace{10pt}
\begin{center}
\includegraphics{polar_curve_6.eps}
\end{center}
\vspace{10pt}
\begin{center}
\includegraphics{polar_curve_7.eps}
\end{center}
\vspace{10pt}
\begin{center}
\includegraphics{polar_curve_8.eps}
\hspace{1in}
\includegraphics{polar_curve_9.eps}
\end{center}</content>
</record>
