Compute Arctangent of y/x
Computes the arc tangent of y/x, using the signs of the two to determine the quadrant of the return value.
Examples in
JavaScript
function calcAngleDegrees(x, y) {
return Math.atan2(y, x) * 180 / Math.PI;
}
console.log(calcAngleDegrees(5, 5));
//expected output: 45
console.log(calcAngleDegrees(10, 10));
//expected output: 45
console.log(calcAngleDegrees(0, 10));
//expected output: 90
Math.atan2(90, 15); // 1.4056476493802699
Math.atan2(15, 90); // 0.16514867741462683
Math.atan2(±0, -0); // ±PI.
Math.atan2(±0, +0); // ±0.
Math.atan2(±0, -x); // ±PI for x > 0.
Math.atan2(±0, x); // ±0 for x > 0.
Math.atan2(-y, ±0); // -PI/2 for y > 0.
Math.atan2(y, ±0); // PI/2 for y > 0.
Math.atan2(±y, -Infinity); // ±PI for finite y > 0.
Math.atan2(±y, +Infinity); // ±0 for finite y > 0.
Math.atan2(±Infinity, x); // ±PI/2 for finite x.
Math.atan2(±Infinity, -Infinity); // ±3*PI/4.
Math.atan2(±Infinity, +Infinity); // ±PI/4.