Math.cos()

{{JSRef}} 

The Math.cos() static method returns the cosine of a number in radians.

{{InteractiveExample("JavaScript Demo: Math.cos()")}} 

function getCircleX(radians, radius) {
  return Math.cos(radians) * radius;
}

console.log(getCircleX(1, 10));
// Expected output: 5.403023058681398

console.log(getCircleX(2, 10));
// Expected output: -4.161468365471424

console.log(getCircleX(Math.PI, 10));
// Expected output: -10

Syntax

Math.cos(x)

Parameters

• x
  • : A number representing an angle in radians.

Return value

The cosine of x, between -1 and 1, inclusive. If x is {{jsxref("Infinity")}} , -Infinity, or {{jsxref("NaN")}} , returns {{jsxref("NaN")}} .

Description

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(-Infinity); // NaN
Math.cos(-0); // 1
Math.cos(0); // 1
Math.cos(1); // 0.5403023058681398
Math.cos(Math.PI); // -1
Math.cos(2 * Math.PI); // 1
Math.cos(Infinity); // NaN

Specifications

{{Specifications}} 

Browser compatibility

{{Compat}} 

See also

• {{jsxref("Math.acos()")}} 
• {{jsxref("Math.asin()")}} 
• {{jsxref("Math.atan()")}} 
• {{jsxref("Math.atan2()")}} 
• {{jsxref("Math.sin()")}} 
• {{jsxref("Math.tan()")}}