PROGRAM LAB4C_VAR20 (INPUT, OUTPUT);
VAR
  A, B, DX: REAL;
  X, Y: REAL;
  K, I: INTEGER;
BEGIN
  WRITELN('PLEASE ENTER A VALUE FOR START A');
  READLN(A);
  WRITELN('PLEASE ENTER A VALUE FOR FINISH B');
  READLN(B);
  WRITELN('PLEASE ENTER A VALUE FOR STEP DX');
  READLN(DX);

  X := A;
  K := TRUNC((B - A) / DX) + 1;

  FOR I := 1 TO K DO
  BEGIN
    IF (1 - ABS(X)) < 0 THEN
      WRITELN('X=', X:8:5, '  Y=IS NOT DEFINED')
    ELSE
    BEGIN
      Y := SQRT((1 - ABS(X)) / (1 + ABS(X)));
      WRITELN('X=', X:8:5, '  Y=', Y:10:5);
    END;

    X := X + DX;
  END;
END.