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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 positive 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 specification of special values.

     cacosh(+-_ + _i) 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                     December 11, 2006                    4th Berkeley Distribution