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/* @(#)w_cosh.c 5.1 93/09/24 */
/*
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
*
* Developed at SunPro, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*/
/*
FUNCTION
<<cosh>>, <<coshf>>---hyperbolic cosine
SYNOPSIS
#include <math.h>
double cosh(double <[x]>);
float coshf(float <[x]>);
DESCRIPTION
<<cosh>> computes the hyperbolic cosine of the argument <[x]>.
<<cosh(<[x]>)>> is defined as
@ifnottex
. (exp(x) + exp(-x))/2
@end ifnottex
@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>>.
PORTABILITY
<<cosh>> is ANSI.
<<coshf>> is an extension.
QUICKREF
cosh ansi pure
coshf - pure
*/
/*
* wrapper cosh(x)
*/
#include "fdlibm.h"
#include <errno.h>
#ifndef _DOUBLE_IS_32BITS
#ifdef __STDC__
double cosh(double x) /* wrapper cosh */
#else
double cosh(x) /* wrapper cosh */
double x;
#endif
{
#ifdef _IEEE_LIBM
return __ieee754_cosh(x);
#else
double z;
z = __ieee754_cosh(x);
if(_LIB_VERSION == _IEEE_ || isnan(x)) return z;
if(fabs(x)>7.10475860073943863426e+02) {
/* cosh(finite) overflow */
#ifndef HUGE_VAL
#define HUGE_VAL inf
double inf = 0.0;
SET_HIGH_WORD(inf,0x7ff00000); /* set inf to infinite */
#endif
errno = ERANGE;
return HUGE_VAL;
} else
return z;
#endif
}
#endif /* defined(_DOUBLE_IS_32BITS) */
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