PHP 7.0.15 Released


(PHP 4 >= 4.1.0, PHP 5, PHP 7)

asinhInverse hyperbolic sine


float asinh ( float $arg )

Returns the inverse hyperbolic sine of arg, i.e. the value whose hyperbolic sine is arg.



The argument to process

Dönen Değerler

The inverse hyperbolic sine of arg

Sürüm Bilgisi

Sürüm: Açıklama
5.3.0 This function is now available on all platforms

Ayrıca Bakınız

add a note add a note

User Contributed Notes 2 notes

ape_cwb at yahoo dot com dot br
9 years ago
The correct implementation of asinh(x) for Windows plataform is:

function asinh($x)
        return ln($x + sqrt(1 + pow($x, 2)));

function ln($x)
     return $x = log($x)/log(M_E);

The worksheet above includes a comparation about the native asinh(x) and the implemented version using LN and LOG (like Snoyes posted on 27-Dec-2005 07:42)

This implementation using LN, give THE SAME results that function asinh(x) linux native.

Allan Patrick Engel
Curitiba - Paraná - Brasil
snoyes at gmail dot com
11 years ago
asinh for windows:

The definition for asinh is asinh(z) = log(z + sqrt(z^2 + 1))

The built-in math functions and operators give poor results for small values of z.  The BCMath version produces closer results, but still quite distant if z < 1.  A BCMath version of the log function might help.

if (!function_exists("asinh")) {
    function asinh($z) {
      return log($z + sqrt($z^2 +1));

if (!function_exists("bcasinh")) {
    function bcasinh($z) {
      return log(bcadd($z, bcsqrt(bcadd(bcpow($z, 2), 1))));
To Top