cpp/numeric/complex/acosh

Computes complex arc hyperbolic cosine of a complex value with branch cut at values less than 1 along the real axis.

Return value
If no errors occur, the complex arc hyperbolic cosine of is returned, in the range of a half-strip of nonnegative values along the real axis and in the interval $[−iπ; +iπ]$ along the imaginary axis.

Error handling and special values
Errors are reported consistent with math_errhandling.

If the implementation supports IEEE floating-point arithmetic,
 * If is, the result is
 * If is  (for any finite x), the result is
 * If is  (for any finite x), the result is  and fe_invalid may be raised.
 * If is  (for any positive finite y), the result is
 * If is  (for any positive finite y), the result is
 * If is, the result is
 * If is, the result is
 * If is  (for any finite y), the result is  and fe_invalid may be raised.
 * If is, the result is
 * If is, the result is
 * If is, the result is