Calculate cosine.
  Performs the trigonometric cosine operation on x returning a value between -1 and 1.

Parameters.

x

Angle expressed in radians (180 degrees = PI radians).

Return Value.
  Cosine of x.

Portability.
  Defined in ANSI-C.
  ANSI-C++ adds float and double overloaded versions of this function, with the same bahavior but being both, parameter and result, of one of these types.

Example.

/* cos example */
#include <stdio.h>
#include <math.h>

#define PI 3.14159265

main ()
{
  double param, result;
  param = 45;
  result = cos (param*PI/180);
  printf ("Cosine of %lf degrees is %lf\n", param, result );
  return 0;
}

See also.
  acos, asin, atan, sin, tan