19if (!function_exists(__NAMESPACE__ .
'\\cos')) {
20 function cos($complex): Complex
22 $complex = Complex::validateComplexArgument($complex);
24 if ($complex->isReal()) {
25 return new Complex(\cos($complex->getReal()));
30 \cos($complex->getReal()) * \cosh($complex->getImaginary()),
31 \sin($complex->getReal()) * \sinh($complex->getImaginary()),
An exception for terminatinating execution or to throw for unit testing.