NAME

cos, cosf, cosl — cosine function

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() function returns the cosine value.

SEE ALSO

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

STANDARDS

The cos() function conforms to ANSI X3.159-1989 (“ANSI C89”).

HISTORY

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