CONST
 Eps=0.0001;
VAR
 Xbeg,Xfin,DX,SUM,X:REAL;
 N:WORD;
 Nx,i:INTEGER;

PROCEDURE SUMS(Xs:REAL; Var S:REAL; Var Ns:WORD);
 VAR
   a:REAL;
 Begin
  a:=Xs;
  S:=Xs;
  Ns:=1;
  Repeat
   Inc(Ns);Inc(Ns);
   a:=a*Xs*Xs;
   S:=S+a/Ns;
  Until Abs(a/Ns)<Eps;
  S:=2*S;
 End;

BEGIN
 Write('Xbeg= ');
 ReadLn(Xbeg);
 Write('Xfin= ');
 ReadLn(Xfin);
 Write('DX= ');
 ReadLn(DX);
 WriteLn;
 WriteLn('         Results of calculation:');
 WriteLn('    X          SUM         N    ln((1+x)/(1-x))');
 WriteLn;
 Nx:=ROUND((Xfin-Xbeg)/DX);
 X:=Xbeg;
 For i:=0 to Nx do
  begin
   X:=Xbeg+DX*i;
   SUMS(X,SUM,N);
   WriteLn(X:8:5,'     ',SUM:8:5,'     ',N:3,'     ',ln((1+x)/(1-x)):8:5);
  end;
 ReadLn;
END.