Return the arc tangent of {expr1} / {expr2}, measured in radians, as a |Float| in the range [-pi, pi]. {expr1} and {expr2} must evaluate to a |Float| or a |Number|. Returns 0.0 if {expr1} or {expr2} is not a |Float| or a |Number|. Examples: :echo atan2(-1, 1) -0.785398 :echo atan2(1, -1) 2.356194 Can also be used as a |method|: Compute()->atan2(1) {only available when compiled with the |+float| feature}