NAME

cos, cosf, cosl — cosine functions

LIBRARY

Math Library (libm, -lm)

SYNOPSIS

#include <math.h>

double
cos(double x);

float
cosf(float x);

long double
cosl(long double x);

DESCRIPTION

The cos(), cosf(), and cosl() functions compute the cosine of x (measured in radians). A large magnitude argument may yield a result with little or no significance. For a discussion of error due to roundoff, see math(3).

RETURN VALUES

The cos(), cosf(), and cosl() functions return the cosine value.

SEE ALSO

acos(3), asin(3), atan(3), atan2(3), ccos(3), cosh(3), math(3), sin(3), sinh(3), tan(3), tanh(3)

STANDARDS

These functions conform to ISO/IEC 9899:1999 (“ISO C99”).

HISTORY

The cos() function first appeared in Version 1 AT&T UNIX.