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COS(P)				    POSIX Programmer's Manual				   COS(P)

       cos, cosf, cosl - cosine function

       #include <math.h>

       double cos(double x);
       float cosf(float x);
       long double cosl(long double x);

       These functions shall compute the cosine of their argument x, measured in radians.

       An  application	wishing  to  check for error situations should set errno to zero and call
       feclearexcept(FE_ALL_EXCEPT) before calling these functions.  On return, if errno is  non-
       zero  or fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero,
       an error has occurred.

       Upon successful completion, these functions shall return the cosine of x.

       If x is NaN, a NaN shall be returned.

       If x is +-0, the value 1.0 shall be returned.

       If x is +-Inf, a domain error shall occur, and either a NaN (if supported), or  an  imple-
       mentation-defined value shall be returned.

       These functions shall fail if:

       Domain Error
	      The x argument is +-Inf.

       If the integer expression (math_errhandling & MATH_ERRNO) is non-zero, then errno shall be
       set to [EDOM]. If the integer expression (math_errhandling & MATH_ERREXCEPT) is	non-zero,
       then the invalid floating-point exception shall be raised.

       The following sections are informative.

   Taking the Cosine of a 45-Degree Angle
	      #include <math.h>
	      double radians = 45 * M_PI / 180;
	      double result;
	      result = cos(radians);

       These  functions  may lose accuracy when their argument is near an odd multiple of pi/2 or
       is far from 0.

       On  error,  the	expressions  (math_errhandling	&  MATH_ERRNO)	and  (math_errhandling	&
       MATH_ERREXCEPT) are independent of each other, but at least one of them must be non-zero.



       acos() , feclearexcept() , fetestexcept() , isnan() , sin() , tan() , the Base Definitions
       volume of IEEE Std 1003.1-2001, Section 4.18, Treatment of Error Conditions for Mathemati-
       cal Functions, <math.h>

       Portions  of  this  text  are  reprinted  and  reproduced in electronic form from IEEE Std
       1003.1, 2003 Edition, Standard for Information Technology  --  Portable	Operating  System
       Interface  (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by
       the Institute of Electrical and Electronics Engineers, Inc and  The  Open  Group.  In  the
       event  of  any  discrepancy  between this version and the original IEEE and The Open Group
       Standard, the original IEEE and The Open Group Standard is the referee document. The orig-
       inal Standard can be obtained online at http://www.opengroup.org/unix/online.html .

IEEE/The Open Group			       2003					   COS(P)
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