[Antidelphik]

помогите пожалуйста исправить ошибки =(, тут самую превую выдает на 51 строке

Код:

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, ExtCtrls, StdCtrls;

type
  TForm1 = class(TForm)
    LabeledEdit1: TLabeledEdit;
    LabeledEdit2: TLabeledEdit;
    LabeledEdit3: TLabeledEdit;
    Memo1: TMemo;
    Button1: TButton;
    Image1: TImage;
    procedure LabeledEdit3Change(Sender: TObject);
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
var
Xmin,Xmax,h,y:real;
cx,cy:real;
begin
try
Xmin:=StrToFloat(LabeledEdit1.Text);
Xmax:=StrToFloat(LabeledEdit2.Text);
h:=StrToFloat(LabeledEdit3.Text);
except
MessageDlg('неверные данные',mtError,[mbOK],0);
exit
end;
if Xmax<=Xmin then
begin
MessageDlg('Xmin>Xmax!',mtError,[mbOK],0);
exit
end;
end;
Memo1.Lines.Clear;
with Image1.Canvas do
 begin
  Brash.Color:=clBlue;
  FillRect(Image1.ClientRect);
  pen.color:=clWhite;
  moveto(0,Image1.Height div 2);
  lineto(Image1.Width,Image1.Height div 2);
  cx:=(Xmax-Xmin)/Image1.Width;
  cy:=2/Image1.Height;
  if cy>cx then
  cx:=cy;
  moveto(0,Image1.Height div 2);
While Xmin<=Xmax do
begin
y:=sin(Xmin);
Memo1.Lines.Add('sin('+FloatToStrF(Xmin,ffFixed,10,4)+')='+FloatToStrF(y,ffFixed,10,4));
lineto(trunc(Xmin/cx),Image1.Height div 2 - trunc(Xmin/cx));
Xmin:=Xmin+h;
end;
end;

end.