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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

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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

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