Manpages - cos.3

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*():

      _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
          || /* Since glibc 2.19: */ _DEFAULT_SOURCE
          || /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

These functions return 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.

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

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

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.

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

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