CACOSH(3)                BSD Library Functions Manual                CACOSH(3)

NAME
     cacosh -- complex inverse hyperbolic cosine function

SYNOPSIS
     double complex
     cacosh(double complex z);

     long double complex
     cacoshl(long double complex z);

     float complex
     cacoshf(float complex z);

DESCRIPTION
     cacosh(z) computes the inverse hyperbolic cosine of the complex floating-
     point number z, with a branch cut on the interval [-inf, 1] along the
     real axis.

     cacosh() returns values in a half-strip of the complex plane with posi-
     tive real part and imaginary part in the interval [-Pi, Pi].

     For all complex floating point numbers z, cacosh(conj(z)) =
     conj(cacosh(z)).

SPECIAL VALUES
     The conjugate symmetry of cacosh() is used to abbreviate the specifica-
     tion of special values.

     cacosh(]-0 ] 0i) returns 0 ] Pi/2 i.

     cacosh(x ] inf i) returns inf ] Pi/2 i, for finite x.

     cacosh(x ] NaN i) returns NaN ] NaN i, for finite nonzero x.

     cacosh(-inf ] yi) returns inf ] Pi i, for finite positive-signed y.

     cacosh(inf ] yi) returns inf ] 0i, for finite positive-signed y.

     cacosh(-inf ] inf i) returns inf ] 3Pi/4 i.

     cacosh(inf ] inf i) returns inf ] Pi/4 i.

     cacosh(]-inf ] NaN i) returns inf ] NaN i.

     cacosh(NaN ] yi) returns NaN ] NaN i, for finite y.

     cacosh(NaN ] inf i) returns inf ] NaN i.

     cacosh(NaN ] NaN i) returns NaN ] NaN i.

NOTES
SEE ALSO
     ccosh(3) complex(3)

STANDARDS
     The cacosh() function conforms to ISO/IEC 9899:1999(E).

4th Berkeley Distribution      November 9, 2006      4th Berkeley Distribution