=over =item atan2 Y,X X X X X Returns the arctangent of Y/X in the range -PI to PI. For the tangent operation, you may use the L|Math::Trig/B> function, or use the familiar relation: sub tan { sin($_[0]) / cos($_[0]) } The return value for C is implementation-defined; consult your L manpage for more information. Portability issues: L. =back