CACOSH(3) Linux Programmer's Manual CACOSH(3)

NAME
       cacosh, cacoshf, cacoshl - complex arc hyperbolic cosine

SYNOPSIS
       #include 

       double complex cacosh(double complex z);
       float complex cacoshf(float complex z);
       long double complex cacoshl(long double complex z);

       Link with -lm.

DESCRIPTION
       The  cacosh()  function calculates the complex arc hyperpolic cosine of
       z.  If y = cacosh(z), then z = ccosh(y).  The imaginary part  of  y  is
       chosen in the interval [-pi,pi].  The real part of y is chosen nonnega‐
       tive.

       One has:

           cacosh(z) = 2 * clog(csqrt((z + 1) / 2) + csqrt((z - 1) / 2))

VERSIONS
       These functions first appeared in glibc in version 2.1.

ATTRIBUTES
       For  an  explanation  of  the  terms  used   in   this   section,   see
       attributes(7).

       ┌───────────────────────────────┬───────────────┬─────────┐
       │Interface                      │ Attribute     │ Value   │
       ├───────────────────────────────┼───────────────┼─────────┤
       │cacosh(), cacoshf(), cacoshl() │ Thread safety │ MT-Safe │
       └───────────────────────────────┴───────────────┴─────────┘
CONFORMING TO
       C99.

EXAMPLE
       /* Link with "-lm" */

       #include 
       #include 
       #include 
       #include 

       int
       main(int argc, char *argv[])
       {
           double complex z, c, f;

           if (argc != 3) {
               fprintf(stderr, "Usage: %s  \n", argv[0]);
               exit(EXITFAILURE);
           }

           z = atof(argv[1]) + atof(argv[2]) * I;

           c = cacosh(z);
           printf("cacosh() = %6.3f %6.3f*i\n", creal(c), cimag(c));

           f = 2 * clog(csqrt((z + 1)/2) + csqrt((z - 1)/2));
           printf("formula  = %6.3f %6.3f*i\n", creal(f2), cimag(f2));

           exit(EXITSUCCESS);
       }

SEE ALSO
       acosh(3), cabs(3), ccosh(3), cimag(3), complex(7)

COLOPHON
       This  page  is  part of release 3.53 of the Linux man-pages project.  A
       description of the project, and information about reporting  bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.



                                  2011-09-15                         CACOSH(3)