Math.tanh()

This is a new technology, part of the ECMAScript 2015 (ES6) standard .
This technology's specification has been finalized, but check the compatibility table for usage and implementation status in various browsers.

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

tanhx=sinhxcoshx=ex-e-xex+e-x=e2x-1e2x+1\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.

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) {
  if (x === Infinity) {
    return 1;
  } else if (x === -Infinity) {
    return -1;
  } else {
    return (Math.exp(x) - Math.exp(-x)) / (Math.exp(x) + Math.exp(-x));
  }
}

or using only one call to Math.exp():

Math.tanh = Math.tanh || function(x) {
  if (x === Infinity) {
    return 1;
  } else if (x === -Infinity) {
    return -1;
  } else {
    var y = Math.exp(2 * x);
    return (y - 1) / (y + 1);
  }
}

Specifications

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

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support 38 25 (25) Not supported 25 7.1
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support Not supported Not supported 25.0 (25) Not supported Not supported 8

See also

Document Tags and Contributors

Contributors to this page: fscholz, Mingun, realityking, kchapelier, fred.wang
Last updated by: fscholz,