===== Tangent ======

==== tan( a ) ====

Return the tangent of a.

=== Description ===

<code>tan( a )</code>

Return the tangent of a in radians.

=== Parameters ===

| ''a'' | Value |

=== Return value ===

Tangent of a in radians

=== Example usage ===

<code>tan( PI/4 )</code>

Returns 1.