Построение sin(x) через vcl

uses vcl;
var
  MainForm: Form;
  L:TextLabel;
  E:Edit;
  B1,B2: Button;
  P:PaintBox;
procedure B1Click;
var x,y,mx,my:real;
    n,i,x0,y0:integer;
begin
n:=strtoint(E.Text);
mx:=10;
my:=20;
for i:=1 to n do
 begin
  x0:=P.width div 2-200+random(401);
  y0:=45+random(51);
  x:=-pi;
  P.Canvas.Pen.Color:=clWhite;
  while x<=pi do
   begin
    if x=-pi then P.Canvas.MoveTo(x0+round(x*mx),y0-round(sin(x)*my))
    else P.Canvas.LineTo(x0+round(x*mx),y0-round(sin(x)*my));
    x:=x+0.01;
   end;
 end;
end;
procedure B2Click;
begin
  MainForm.Close;
end;
 
begin
  randomize;
  MainForm:=Form.Create(Screen.Width div 2-250,Screen.Height div 2-250,500,500);
  MainForm.Caption:='SIN';
  L:=TextLabel.Create(20,435,30,25);
  L.Caption:='N=';
  E:=Edit.Create(50,430,100,25);
  B1:=Button.Create(200,430,100,25);
  B1.Caption:='Íàðèñîâàòü';
  B1.OnClick:=B1Click;
  B2:=Button.Create(350,430,100,25);
  B2.Caption:='Âûõîä';
  B2.OnClick:=B2Click;
  P:=PaintBox.Create(20,20,450,400);
  P.Canvas.Brush.Color:=clBlue;
  P.Canvas.rectangle(0,0,P.width,P.height);
end.