Math.tanh

The Math.tanh() function returns the hyperbolic tangent of a number, that is

$$\tanh x = \frac{\sinh x}{\cosh x} = \frac {e^x - e^{-x}} {e^x + e^{-x}} = \frac{e^{2x} - 1}{e^{2x}+1}$$

Syntax

Math.tanh(x)

Parameters

x

A number.

Return value

The hyperbolic tangent of the given number.

Description

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

Examples

Using Math.tanh()

Math.tanh(0);        // 0
Math.tanh(Infinity); // 1
Math.tanh(1);        // 0.7615941559557649

Polyfill

This can be emulated with the help of the Math.exp() function:

Math.tanh = Math.tanh || function(x){
    var a = Math.exp(+x), b = Math.exp(-x);
    return a == Infinity ? 1 : b == Infinity ? -1 : (a - b) / (a + b);
}

Specifications

Specification	Status	Comment
ECMAScript 2015 (6th Edition, ECMA-262) The definition of 'Math.tanh' in that specification.	Standard	Initial definition.
ECMAScript 2017 Draft (ECMA-262) The definition of 'Math.tanh' in that specification.	Draft

Browser compatibility

See also

• Math.acosh()
• Math.asinh()
• Math.atanh()
• Math.cosh()
• Math.sinh()