Displaying a noisy line, a fitted line and a cross hair with TAChart

{http://wiki.lazarus.freepascal.org/TAChart}

procedure TForm1.Button1Click(Sender: TObject);
var
  Serie:TTASerie;
  i:Integer;
begin
Serie:=TTASerie.Create(TAChart1);
TAChart1.AddSerie(Serie);
Serie.ShowLines:=True;
Serie.ShowPoints:=False;
Serie.Title:='Sinus';
for i:=-500 to 499 do
   Serie.AddXY(i/10,Sin(i/10)*10,clBlack);
end;