cos (3)

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NAME

cos, cosf, cosl - cosine function

SYNOPSIS

#include <math.h>

double cos(double x);


float cosf(float x);


long double cosl(long double x);

Link with -lm.

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

cosf(), cosl():

_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L;
or cc -std=c99

DESCRIPTION

The cos() function returns the cosine of x, where x is given in radians.

RETURN VALUE

On success, these functions return the cosine of x.

If x is a NaN, a NaN is returned.

If x is positive infinity or negative infinity, a domain error occurs, and a NaN is returned.

ERRORS

See math_error(7) for information on how to determine whether an error has occurred when calling these functions.

The following errors can occur:

Domain error: x is an infinity

errno is set to EDOM (but see BUGS). An invalid floating-point exception (FE_INVALID) is raised.

CONFORMING TO

C99, POSIX.1-2001. The variant returning double also conforms to SVr4, 4.3BSD.

BUGS

Before version 2.10, the glibc implementation did not set errno to EDOM when a domain error occurred.

SEE ALSO

acos(3), asin(3), atan(3), atan2(3), ccos(3), sin(3), sincos(3), tan(3)

COLOPHON

This page is part of release 3.54 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.

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