Const
 Eps=0.00001;
VAR
 N,i,k:Word;
 Xbeg,Xfin,Dx,S,X,a:Real;

BEGIN
 Write('Xbeg= ');
 ReadLn(Xbeg);
 Write('Xfin= ');
 ReadLn(Xfin);
 Write('DX= ');
 ReadLn(DX);
 N:=Round((Xfin-Xbeg)/DX);
 WriteLn('   X        Result      Number of items     Accurate value');
 For i:=0 to N do
  begin
   X:=Xbeg+DX*i;
   S:=-Pi/2-1.0/X;
   k:=0;
   a:=-1.0/X;
   Repeat
    Inc(k);
    a:=-a/SQR(X)*(2*k-1)/(2*k+1);
    S:=S+a;
   Until Abs(a)<Eps;
   WriteLn(X:6:3,S:12:3,k:12,ArcTan(X):24:3);
  end;
 Readln;
END.