


      ATAN(3F)                    (UNIX 5.0)                   ATAN(3F)



      NAME
           atan, datan - Fortran arctangent intrinsic function

      SYNTAX
           real r1, r2
           double precision dp1, dp2

           r2 = atan(r1)

           dp2 = datan(dp1)
           dp2 = atan(dp1)

      DESCRIPTION
           Atan returns the arctangent of its argument, in real or
           double-precision type that matches the argument.

           Datan returns the double-precision arctangent of its
           double-precsion argument.

           Although Atan works for either data type, datan is for
           clarity in programming.

      SEE ALSO
           trig(3M).































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