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cos, cosf, cosl - cosine function
#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
The cos() function returns the cosine of x, where x is given in radians.
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.
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.
C99, POSIX.1-2001. The variant returning double also conforms to SVr4, 4.3BSD.
Before version 2.10, the glibc implementation did not set errno to EDOM when a domain error occurred.
This page is part of release 3.35 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://man7.org/linux/man- pages/. 2010-09-11 COS(3)