PHPKonf İstanbul PHP Conference 2015

# asinh

(PHP 4 >= 4.1.0, PHP 5)

asinhSeno Hiperbólico Inverso

### Descrição

float asinh ( float `\$arg` )

Retorna o inverso do seno hiperbólico de `arg`, isto é, o valor cujo seno hiperbólico é `arg`.

Nota: esta função não é implementada na plataforma Windows

### Parâmetros

`arg`

O argumento para processar

O seno hiperbólico inverso de `arg`

### Veja Também

• sinh() - Seno hiperbólico
• asin() - Seno Inverso (arco seno)
• acosh() - Cosseno Hiperbólico Inverso
• atanh() - Tangente hiperbólica inversa

``` 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) http://www.mavadesign.com.br/allan/asinh(x).xlsThis implementation using LN, give THE SAME results that function asinh(x) linux native.Allan Patrick EngelCuritiba - Paraná - Brasil ```
``` 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))));    }} ```