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* Chickadee: (chickadee). Game programming toolkit for Guile.
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<title>Basics (The Chickadee Game Toolkit)</title>
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Next: <a href="Vectors.html#Vectors" accesskey="n" rel="next">Vectors</a>, Up: <a href="Math.html#Math" accesskey="u" rel="up">Math</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
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<a name="Basics-1"></a>
<h4 class="subsection">2.2.1 Basics</h4>
<dl>
<dt><a name="index-pi"></a>Variable: <strong>pi</strong></dt>
<dd><p>An essential constant for all trigonometry. Pi is the ratio of a
circle’s circumferences to its diameter. Since pi is an irrational
number, the <var>pi</var> in Chickadee is a mere floating point
approximation that is “good enough.”
</p></dd></dl>
<dl>
<dt><a name="index-pi_002f2"></a>Variable: <strong>pi/2</strong></dt>
<dd><p>Half of <var>pi</var>.
</p></dd></dl>
<dl>
<dt><a name="index-cotan"></a>Procedure: <strong>cotan</strong> <em>z</em></dt>
<dd><p>Return the cotangent of <var>z</var>.
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