Returns the cosine of its radian argument.

    Format

      #include  <math.h>

      double cos  (double x);

      float cosf  (float x); (Integrity servers, Alpha)

      long double cosl  (long double x); (Integrity servers, Alpha)

      double cosd  (double x); (Integrity servers, Alpha)

      float cosdf  (float x); (Integrity servers, Alpha)

      long double cosdl  (long double x); (Integrity servers, Alpha)

1  –  Argument

 x

    A radian expressed as a real value.

2  –  Description

    The cos functions return the cosine of their argument, measured
    in radians.

    The cosd functions return the cosine of their argument, measured
    in degrees.

    |x| = Infinity is an invalid argument.

3  –  Return Values

    x                  The cosine of the argument.
    HUGE_VAL           Indicates that the argument is too large;
                       errno is set to ERANGE.