atanh.php
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<?php
/**
*
* Function code for the complex atanh() function
*
* @copyright Copyright (c) 2013-2018 Mark Baker (https://github.com/MarkBaker/PHPComplex)
* @license https://opensource.org/licenses/MIT MIT
*/
namespace Complex;
/**
* Returns the inverse hyperbolic tangent of a complex number.
*
* @param Complex|mixed $complex Complex number or a numeric value.
* @return Complex The inverse hyperbolic tangent of the complex argument.
* @throws Exception If argument isn't a valid real or complex number.
*/
function atanh($complex)
{
$complex = Complex::validateComplexArgument($complex);
if ($complex->isReal()) {
$real = $complex->getReal();
if ($real >= -1.0 && $real <= 1.0) {
return new Complex(\atanh($real));
} else {
return new Complex(\atanh(1 / $real), (($real < 0.0) ? M_PI_2 : -1 * M_PI_2));
}
}
$iComplex = clone $complex;
$iComplex = $iComplex->invertImaginary()
->reverse();
return atan($iComplex)
->invertReal()
->reverse();
}