In Cool§
See primary documentation in context for routine atan
sub atan(Numeric(Cool)) method atan()
Coerces the invocant (or in sub form, the argument) to Numeric
, and returns its arc-tangent in radians.
say atan(3); # OUTPUT: «1.24904577239825» say 3.atan; # OUTPUT: «1.24904577239825»