Построить график функции

uses graphABC;
function f1(x:real):real;
begin
f1:=10*sin(x);
end;
function f2(x:real):real;
begin
f2:=x*x;
end;
function f3(x:real):real;
begin
f3:=x;
end;
 
var xn,xk,x,m,dx:real;
    x0,y0,i:integer;
begin
xn:=-pi;xk:=pi;
setwindowsize(400,700);
centerwindow;
x0:=windowwidth div 2;
y0:=windowheight div 2;
m:=(y0-30)/f2(xk);
line(x0-round((xk+1)*m),y0,x0+round((xk+1)*m),y0);
line(x0,0,x0,windowheight);
for i:=1 to trunc(f2(xk))+1 do
 begin
  line(x0-3,y0-round(i*m),x0+3,y0-round(i*m));
  textout(x0-20,y0-round(i*m),inttostr(i));
  if i<5 then
   begin
    line(x0-3,y0+round(i*m),x0+3,y0+round(i*m));
    textout(x0-25,y0+round(i*m),inttostr(-i));
    line(x0+round(i*m),y0-3,x0+round(i*m),y0+3);
    line(x0-round(i*m),y0-3,x0-round(i*m),y0+3);
    textout(x0+round(i*m),y0+10,inttostr(i));
    textout(x0-round(i*m),y0+10,inttostr(-i));
   end;
 end;
textout(x0+5,y0+10,'0');
textout(x0+round((xk+1)*m),y0-20,'X');
textout(x0+5,10, 'Y');
x:=xn;
dx:=0.01;
setpencolor(clRed);
moveto(x0+round(x*m),y0-round(f1(xn)*m));
while x<=xk do
 begin
  lineto(x0+round(x*m),y0-round(f1(x)*m));
  x:=x+dx;
 end;
x:=xn;
setpencolor(clBlue);
moveto(x0+round(x*m),y0-round(f2(xn)*m));
while x<=xk do
 begin
  lineto(x0+round(x*m),y0-round(f2(x)*m));
  x:=x+dx;
 end;
x:=xn;
setpencolor(clGreen);
moveto(x0+round(x*m),y0-round(f3(xn)*m));
while x<=xk do
 begin
  lineto(x0+round(x*m),y0-round(f3(x)*m));
  x:=x+dx;
 end;
setfontsize(12);
setfontcolor(clRed);
textout(x0+20,y0+40,'y=10sinx');
setfontcolor(clBlue);
textout(x0+20,y0+60,'y=x^2');
setfontcolor(clGreen);
textout(x0+20,y0+80,'y=x');
setfontcolor(clBlack);
textout(x0+20,y0+100,'на интервале [-pi;pi]');
end.