Math

`Math.cos`

Returns the cosine of a number in radians

Syntax

JavaScript

Math.cos(x)

Parameters

Parameter	Type	Description
x	number	An angle in radians

Return Value

The cosine of x, between -1 and 1

Examples

Basic Usage

console.log(Math.cos(0)); // 1
console.log(Math.cos(Math.PI)); // -1

Practical Example

function polarToCartesian(r: number, theta: number) {
  return { x: r * Math.cos(theta), y: r * Math.sin(theta) };
}
console.log(polarToCartesian(1, 0)); // { x: 1, y: 0 }

Advanced Usage

const angle = Math.PI / 3; // 60 degrees
console.log(Math.cos(angle)); // 0.5

Understanding Math.cos

The Math.cos method in JavaScript returns the cosine of a number in radians. It belongs to the Math object and is one of the most widely used methods for working with math values in modern JavaScript and TypeScript applications.

The method signature is Math.cos(x). It accepts 1 parameter: x. When called, it returns the cosine of x, between -1 and 1. Understanding when and how to use cos() helps you write more expressive, readable code.

Common use cases for Math.cos include data transformation, input validation, API response processing, and building reusable utility functions. It works well alongside related methods like math-sin, math-tan, math-pi, enabling you to chain operations together for complex data manipulation pipelines.

Browser support for Math.cos is excellent across all modern browsers including Chrome, Firefox, Safari, and Edge. It is also fully supported in Node.js and Deno. For older environments, transpilation with Babel or a polyfill may be needed.