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