1<?php
2
3/**
4 *
5 * Function code for the complex asech() function
6 *
7 * @copyright  Copyright (c) 2013-2018 Mark Baker (https://github.com/MarkBaker/PHPComplex)
8 * @license    https://opensource.org/licenses/MIT    MIT
9 */
10namespace Complex;
11
12/**
13 * Returns the inverse hyperbolic secant of a complex number.
14 *
15 * @param     Complex|mixed    $complex    Complex number or a numeric value.
16 * @return    Complex          The inverse hyperbolic secant of the complex argument.
17 * @throws    Exception        If argument isn't a valid real or complex number.
18 * @throws    \InvalidArgumentException    If function would result in a division by zero
19 */
20function asech($complex)
21{
22    $complex = Complex::validateComplexArgument($complex);
23
24    if ($complex->getReal() == 0.0 && $complex->getImaginary() == 0.0) {
25        return INF;
26    }
27
28    return acosh(inverse($complex));
29}
30