The Math.atan() static method returns the inverse tangent (in radians) of a number, that is
πΌπππ.ππππ(π‘)=arctan(x)=the unique yβ[βΟ2,Ο2] such that tan(y)=x\mathtt{\operatorname{Math.atan}(x)} = \arctan(x) = \text{the unique } y \in \left[-\frac{\pi}{2}, \frac{\pi}{2}\right] \text{ such that } \tan(y) = x
Syntax
Math.atan(x)
Parameters
x- : A number.
Return value
The inverse tangent (angle in radians between -Ο2-\frac{\pi}{2} and Ο2\frac{\pi}{2}, inclusive) of x. If x is Infinity, it returns Ο2\frac{\pi}{2}. If x is -Infinity, it returns -Ο2-\frac{\pi}{2}.
Description
Because atan() is a static method of Math, you always use it as Math.atan(), rather than as a method of a Math object you created (Math is not a constructor).
Examples
Using Math.atan()
Math.atan(-Infinity); // -1.5707963267948966 (-Ο/2)
Math.atan(-0); // -0
Math.atan(0); // 0
Math.atan(1); // 0.7853981633974483 (Ο/4)
Math.atan(Infinity); // 1.5707963267948966 (Ο/2)
// The angle that the line (0,0) -- (x,y) forms with the x-axis in a Cartesian coordinate system
const theta = (x, y) => Math.atan(y / x);
Note that you may want to avoid the theta function and use Math.atan2 instead, which has a wider range (between -Ο and Ο) and avoids outputting NaN for cases such as when x is 0.