acos(3) [freebsd man page]

ACOS(3) 						   BSD Library Functions Manual 						   ACOS(3)

NAME

     acos, acosf, acosl -- arc cosine functions

LIBRARY

     Math Library (libm, -lm)

SYNOPSIS

     #include <math.h>

     double
     acos(double x);

     float
     acosf(float x);

     long double
     acosl(long double x);

DESCRIPTION

     The acos(), acosf(), and acosl() functions compute the principal value of the arc cosine of x.

RETURN VALUES

     These functions return the arc cosine in the range [0, pi] radians.  If:

	   |x| > 1,

     acos(x) raises an invalid exception and returns an NaN.

SEE ALSO

     asin(3), atan(3), atan2(3), cos(3), cosh(3), fenv(3), math(3), sin(3), sinh(3), tan(3), tanh(3)

STANDARDS

     The acos(), acosf(), and acosl() functions conform to ISO/IEC 9899:1999 (``ISO C99'').

BSD
								   July 31, 2008							       BSD

ACOS(3) 						   BSD Library Functions Manual 						   ACOS(3)

NAME

     acos -- arc cosine function

SYNOPSIS

     #include <math.h>

     double
     acos(double x);

     long double
     acosl(long double x);

     float
     acosf(float x);

DESCRIPTION

     The acos() function computes the principle value of the arc cosine of x.  The result is in the range [0, pi].

SPECIAL VALUES

     acos(1) returns +0.

     acos(x) returns a NAN and raises the "invalid" floating-point exception for |x| > 1.

VECTOR OPERATIONS

     If you need to apply the acos() function to SIMD vectors or arrays, using the following functions provided by the Accelerate.framework may
     give significantly better performance:

     #include <Accelerate/Accelerate.h>

     vFloat vacosf(vFloat x);
     void vvacosf(float *y, const float *x, const int *n);
     void vvacos(double *y, const double *x, const int *n);

SEE ALSO

     sin(3), cos(3), tan(3), asin(3), atan(3), atan2(3), sinh(3), cosh(3), tanh(3), math(3)

STANDARDS

     The acos() function conforms to ISO/IEC 9899:2011.

BSD
								 December 11, 2006							       BSD