Synopsis
atan2 y, x
Returns the arctangent of
y
/
x
in the range -π to π. A quick way to
get an approximate value of π is to say:
$pi = atan2(1,1) * 4;
For the tangent operation, you may use the POSIX::tan( )
function, or use the
familiar relation:
sub tan { sin($_[0]) / cos($_[0]) }