cos, cosf, cosl − cosine function

#include <math.h>

double cos(double x);

float cosf(float x);

long double cosl(long double x);

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

The cos() function returns a value between −1 and 1.

SVID 3, POSIX, BSD 4.3, ISO 9899. The float and the long double variants are C99 requirements.

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