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/* @(#)z_cosh.c 1.0 98/08/13 */
 
/*
 
FUNCTION
        <<cosh>>, <<coshf>>---hyperbolic cosine
 
ANSI_SYNOPSIS
        #include <math.h>
        double cosh(double <[x]>);
        float coshf(float <[x]>)
 
TRAD_SYNOPSIS
        #include <math.h>
        double cosh(<[x]>)
        double <[x]>;
 
        float coshf(<[x]>)
        float <[x]>;
 
DESCRIPTION
 
        <<cosh>> computes the hyperbolic cosine of the argument <[x]>.
        <<cosh(<[x]>)>> is defined as
        @ifinfo
        . (exp(x) + exp(-x))/2
        @end ifinfo
        @tex
        $${(e^x + e^{-x})} \over 2$$
        @end tex
 
        Angles are specified in radians.
 
        <<coshf>> is identical, save that it takes and returns <<float>>.
 
RETURNS
        The computed value is returned.  When the correct value would create
        an overflow,  <<cosh>> returns the value <<HUGE_VAL>> with the
        appropriate sign, and the global value <<errno>> is set to <<ERANGE>>.
 
        You can modify error handling for these functions using the
        function <<matherr>>.
 
PORTABILITY
        <<cosh>> is ANSI.
        <<coshf>> is an extension.
 
QUICKREF
        cosh ansi pure
        coshf - pure
*/
 
/******************************************************************
 * Hyperbolic Cosine
 *
 * Input:
 *   x - floating point value
 *
 * Output:
 *   hyperbolic cosine of x
 *
 * Description:
 *   This routine returns the hyperbolic cosine of x.
 *
 *****************************************************************/
 
#include "fdlibm.h"
#include "zmath.h"
 
#ifndef _DOUBLE_IS_32BITS
 
double
_DEFUN (cosh, (double),
        double x)
{
  return (sineh (x, 1));
}
 
#endif /* _DOUBLE_IS_32BITS */