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():

DESCRIPTION¶

These functions return 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.

ATTRIBUTES¶

For an explanation of the terms used in this section, see attributes(7).

CONFORMING TO¶

C99, POSIX.1-2001, POSIX.1-2008.

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¶

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