std::acos(std::complex)

From cppreference.com
Defined in header <complex>
template< class T >
complex<T> acos( const complex<T>& z );
(since C++11)

Computes complex arc cosine of a complex value z. Branch cut exists outside the interval [−1 ; +1] along the real axis.

[edit] Parameters

z - complex value

[edit] Return value

Complex arc cosine of z in the range [0 ; ∞) along the real axis and in the range [−iπ ; iπ] along the imaginary axis.

[edit] See also

computes arc sine of a complex number (arcsin(z))
(function template)
computes arc tangent of a complex number (arctan(z))
(function template)