Trailing-Edge
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PDP-10 Archives
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SRI_NIC_PERM_FS_1_19910112
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c/lib/math/sinh.c
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/*
* +++ NAME +++
*
* SINH Double precision hyperbolic sine
*
* +++ INDEX +++
*
* SINH
* machine independent routines
* math libraries
*
* +++ DESCRIPTION +++
*
* Returns double precision hyperbolic sine of double precision
* floating point number.
*
* +++ USAGE +++
*
* double sinh(x)
* double x;
*
* +++ REFERENCES +++
*
* Fortran IV plus user's guide, Digital Equipment Corp. pp B-5
*
* +++ RESTRICTIONS +++
*
* Inputs greater than LN(DBL_MAX) result in overflow.
* Inputs less than LN(DBL_MIN) result in underflow.
*
* For precision information refer to documentation of the
* floating point library routines called.
*
* +++ PROGRAMMER +++
*
* Fred Fish
* Goodyear Aerospace Corp, Arizona Div.
* (602) 932-7000 work
* (602) 894-6881 home
*
* Modifications for inclusion in standard C library are
* (c) Copyright Ian Macky, SRI International 1985
* Additional modifications after v.3, 2-Jul-1986 are
* (c) Copyright Ken Harrenstien 1989
*
* This routine now conforms with the description of the sinh()
* function as defined in
* Harbison & Steele's "C: A Reference Manual", section 11.3.22
*
* +++ INTERNALS +++
*
* Computes hyperbolic sine from:
*
* sinh(X) = 0.5 * (exp(X) - exp(-X))
*
* ---
*/
#include <math.h>
#include <errno.h>
#include "pml.h"
double sinh(x)
double x;
{
if (x > LN_MAXPOSDBL) {
errno = ERANGE;
return HUGE_VAL;
}
if (x < LN_MINPOSDBL) {
errno = ERANGE;
return 0.0;
}
return 0.5 * (exp(x) - exp(-x));
}