Math.atan()
Baseline Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.
The Math.atan()
static method returns the inverse tangent (in radians) of a number, that is
Try it
Syntax
js
Math.atan(x)
Parameters
x
-
A number.
Return value
The inverse tangent (angle in radians between and , inclusive) of x
. If x
is Infinity
, it returns . If x
is -Infinity
, it returns .
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()
js
Math.atan(-Infinity); // -1.5707963267948966 (-π/2)
Math.atan(-0); // -0
Math.atan(0); // 0
Math.atan(1); // 0.7853981633974483 (π/4)
Math.atan(Infinity); // 1.5707963267948966 (π/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 -π and π) and avoids outputting NaN
for cases such as when x
is 0
.
Specifications
Specification |
---|
ECMAScript Language Specification # sec-math.atan |
Browser compatibility
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