===== Sine ======

==== sin( a ) ====

Return the sine of a.

=== Description ===

<code>sin( a )</code>

Return the sine of a, where a is the angle in radians.

=== Parameters ===

| ''a'' | Angle in radians |

=== Return value ===

sine of a

=== Example usage ===

<code>sin( PI/2 )</code>

Returns 1.