Math.cos() - JavaScript 编辑

The Math.cos() static function returns the cosine of the specified angle, which must be specified in radians. This value is ${\displaystyle \frac{{\text{length}}_{\text{adjacent}}}{{\text{length}}_{\text{hypotenuse}}}}$.

The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.

The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.

Syntax

Math.cos(x)

Parameters

x

The angle in radians for which to return the cosine.

Return value

The cosine of the given number.

Description

The Math.cos() method returns a numeric value between -1 and 1, which represents the cosine of the angle.

Because cos() is a static method of Math, you always use it as Math.cos(), rather than as a method of a Math object you created (Math is not a constructor).

Examples

Using Math.cos()

Math.cos(0);           // 1
Math.cos(1);           // 0.5403023058681398

Math.cos(Math.PI);     // -1
Math.cos(2 * Math.PI); // 1

Specifications

Specification
ECMAScript (ECMA-262) The definition of 'Math.cos' in that specification.

Browser compatibility

BCD tables only load in the browser

See also

• Math.acos()
• Math.asin()
• Math.atan()
• Math.atan2()
• Math.sin()
• Math.tan()