atan2y

atan2y is a term encountered in some programming and mathematical contexts to refer to a two-argument arctangent function, typically an alias or wrapper around atan2. The standard name for this functionality is atan2(y, x), and the exact behavior is defined by the library or language being used.

The function returns the angle θ between the positive x-axis and the point with coordinates (x, y). It accounts for the signs of both arguments to place θ in the correct quadrant, producing a result in the range (-π, π], usually expressed in radians. In many languages, you can obtain the same result by converting to degrees if needed: angle_degrees = atan2(y, x) * 180/π.

Usage and examples: atan2y(y, x) yields θ such that tan(θ) = y/x with the quadrant determined by x and y. For example, atan2y(1, 1) is π/4 (45 degrees); atan2y(1, −1) is 3π/4 (135 degrees); atan2y(−1, 0) is −π/2 (−90 degrees). If y = 0 and x > 0, the result is 0; if y = 0 and x < 0, the result is π. Special cases such as x = 0 or y = 0 can behave differently across libraries, so consulting the specific language’s documentation is advised. When used in polar coordinates, θ = atan2(y, x) and r = sqrt(x^2 + y^2).

Relation to atan2: atan2y is most often just another name or a thin wrapper for the standard two-argument arctangent. It is not universally standardized, so its exact spelling, signature, and return conventions may vary by environment.