---

uses graphabc;
function f(x:end);end 
begin f:=sin(x) end,
begin line(0;240,640,240);
line (320,0,320,480);
line (640,240,635,235);
line (640,240,635,245);
textout (635,250,"x");
for x:=1 to 15 do
  line (x40, 238,x40.,242);