program ARCCOT ;
var J : integer ; x, y, z : extended ;

BEGIN Writeln('ARCCOT.PAS') ;
Writeln('   J    x=J/3   arctan(x)   arctan(1/x)   '+
  'Pi/2-arctan(x)  difference') ;
for J := -10 to 10 do begin x := J/3 ;
  Write(J:4, x:9:3, arctan(x):12:6) ;
  if J<>0 then begin y := arctan(1/x) ; Write(y:14:6) end
  else Write('---------':14) ;
  z := 0.5*Pi-arctan(x) ; Write(z:17:6) ;
  if J<>0 then Write(y-z:12:6) ;
  Writeln end ;
Readln ;
END.
N.B. z is better than y, because it is continuous across the range.
See FPATAN2.PAS for a better ARCTAN.
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