cos() computes the cosine of x, measured in radians.
    cosd() computes the cosine of x, measured in degrees.
                           Entry-Point Names
    Generic                               Compaq
    Function   Data Type   OpenVMS        Tru64 UNIX
    Name       Required    Alpha          Alpha
    cos        S_FLOAT     math$cos_s     cosf
               T_FLOAT     math$cos_t     cos
               X_FLOAT     math$cos_x     cosl
               F_FLOAT     math$cos_f
               G_FLOAT     math$cos_g
    cosd       S_FLOAT     math$cosd_s    cosdf
               T_FLOAT     math$cosd_t    cosd
               X_FLOAT     math$cosd_x    cosdl
               F_FLOAT     math$cosd_f
               G_FLOAT     math$cosd_g