Perl 5 version 12.4 documentation


  • atan2 Y,X

    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:

    1. sub tan { sin($_[0]) / cos($_[0]) }

    The return value for atan2(0,0) is implementation-defined; consult your atan2(3) manpage for more information.