Math.tan()

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.tan() static method returns the tangent of a number in radians.

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Syntax

js
Math.tan(x)

Parameters

x

A number representing an angle in radians.

Return value

The tangent of x. If x is Infinity, -Infinity, or NaN, returns NaN.

Note: Due to floating point precision, it's not possible to obtain the exact value π/2, so the result is always finite if not NaN.

Description

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

Examples

Using Math.tan()

js
Math.tan(-Infinity); // NaN
Math.tan(-0); // -0
Math.tan(0); // 0
Math.tan(1); // 1.5574077246549023
Math.tan(Math.PI / 4); // 0.9999999999999999 (Floating point error)
Math.tan(Infinity); // NaN

Math.tan() and π/2

It's not possible to calculate tan(π/2) exactly.

js
Math.tan(Math.PI / 2); // 16331239353195370
Math.tan(Math.PI / 2 + Number.EPSILON); // -6218431163823738

Using Math.tan() with a degree value

Because the Math.tan() function accepts radians, but it is often easier to work with degrees, the following function accepts a value in degrees, converts it to radians and returns the tangent.

js
function getTanDeg(deg) {
  const rad = (deg * Math.PI) / 180;
  return Math.tan(rad);
}

Specifications

Specification
ECMAScript Language Specification
# sec-math.tan

Browser compatibility

BCD tables only load in the browser

See also