Description

   atan() computes the principal value of the arc tangent of x
   in the interval [-pi/2,pi/2] radians for x in the interval [-
   infinity, +infinity].

   atand() computes the principal value of the arc tangent of x in
   the interval [-90,90] degrees for x in the interval [-infinity,
   +infinity].


                          Entry-Point Names

   Generic
   Function   Data Type   OpenVMS        Tru64 UNIX
   Name       Required

   atan       S_FLOAT     math$atan_s    atanf
              T_FLOAT     math$atan_t    atan
              X_FLOAT     math$atan_x    atanl
              F_FLOAT     math$atan_f
              G_FLOAT     math$atan_g

   atand      S_FLOAT     math$atand_s   atandf
              T_FLOAT     math$atand_t   atand
              X_FLOAT     math$atand_x   atandl
              F_FLOAT     math$atand_f
              G_FLOAT     math$atand_g