JavaScript Math.cos()
Examples
let x = Math.cos(3.14);
Try it Yourself »
Math.cos(0);
Math.cos(Math.PI);
Math.cos(2 * Math.PI);
Try it Yourself »
Math.cos(x) expects x radians.
To use degrees, convert the degrees to radians.
Math.cos(degree * Math.PI / 180);
Try it Yourself »
Definition and Usage
The Math.cos()
method returns the cosine of a number.
The Math.cos()
method returns a number between -1 and 1.
The Math.cos()
method expects the number in radians.
What is Radians?
Radians is an angle's α amount of rotation b on a circle:
![Radian](img_radian.jpg)
Degrees | PI | Radians |
---|---|---|
0° | 0 | 0 |
1° | PI/180 | 0.0175 |
30° | PI/6 | 0.52 |
45° | PI/4 | 0.79 |
90° | PI/2 | 1.57 |
180° | PI | 3.14 |
360° | PI*2 | 6.28 |
JavaScript Sine and Cosine Methods:
The Math.sin() MethodThe Math.sinh() Method
The Math.asin() Method
The Math.asinh() Method
The Math.cos() Method
The Math.cosh() Method
The Math.acos() Method
The Math.acosh() Method
Syntax
Math.cos(x)
Parameter
Parameter | Description |
x | Required. A number representing radians. |
Return Value
Type | Description |
Number | -1 to 1 The cosine of the number.NaN if the parameter is not numeric. |
The Pythagoran Therorem
Math.sin()
, Math.cos()
,
and Math.tan()
are related to the Pythagorean theorem:
![Pythagoras](img_angle.jpg)
Theorem: c2 = a2 = b2
The sine Math.sin()
to the angle is a / c.
The cosine Math.cos()
to the angle is b / c.
The tangent Math.tan()
to the angle is a / b.
Browser Support
Math.cos()
is an ECMAScript1 (ES1) feature.
ES1 (JavaScript 1997) is fully supported in all browsers:
Chrome | IE | Edge | Firefox | Safari | Opera |
Yes | Yes | Yes | Yes | Yes | Yes |