/* atan.c - math routines *//* Copyright 1992-1994 Wind River Systems, Inc. *//*modification history--------------------01d,09dec94,rhp  fix man pages for inverse trig fns01e,05feb93,jdi  doc changes based on kdl review.01d,02dec92,jdi  doc tweaks.01c,28oct92,jdi  documentation cleanup.01b,20sep92,smb  documentation additions01a,08jul92,smb  documentation.*//*DESCRIPTION* Copyright (c) 1985 Regents of the University of California.* All rights reserved.** Redistribution and use in source and binary forms are permitted* provided that the above copyright notice and this paragraph are* duplicated in all such forms and that any documentation,* advertising materials, and other materials related to such* distribution and use acknowledge that the software was developed* by the University of California, Berkeley.  The name of the* University may not be used to endorse or promote products derived* from this software without specific prior written permission.* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.** All recipients should regard themselves as participants in an ongoing* research project and hence should feel obligated to report their* experiences (good or bad) with these elementary function codes, using* the sendbug(8) program, to the authors.SEE ALSO: American National Standard X3.159-1989NOMANUAL*/#include "vxWorks.h"#include "math.h"/********************************************************************************* atan - compute an arc tangent (ANSI)** This routine returns the principal value of the arc tangent of <x> in* double precision (IEEE double, 53 bits).* If <x> is the tangent of an angle <T>, this function returns <T> * (in radians).** INCLUDE FILES: math.h** RETURNS:* The double-precision arc tangent of <x> in the range [-pi/2,pi/2] radians.* Special case:	if <x> is NaN, atan() returns <x> itself.** SEE ALSO: mathALib** INTERNAL:* Coded in C by K.C. Ng, 4/16/85, revised on 6/10/85.*/double atan    (    double x	/* tangent of an angle */    )    {	double atan2(),one=1.0;	return(atan2(x,one));    }