Returns the arctangent of Y/X in the range -PI to PI.
For the tangent operation, you may use the Math::Trig::tan function, or use the familiar relation:
sub tan { sin($_[0]) / cos($_[0]) }The return value for atan2(0,0) is implementation-defined; consult your atan2(3) manpage for more information.
Portability issues: "atan2" in perlport.