`pub fn atan2(y: f64, x: f64) -> f64`

## Expand description

Arctangent of y/x (f64)

Computes the inverse tangent (arc tangent) of `y/x`

.
Produces the correct result even for angles near pi/2 or -pi/2 (that is, when `x`

is near 0).
Returns a value in radians, in the range of -pi to pi.