Program Funkcja_pierwotna;
uses graph;
var karta,tryb,n,j,k:integer;
    x,Dx,pierwotna:real;
function f(x:real):real;
begin
  f:=cos(x);
end;
begin
  karta:=detect; initgraph(karta,tryb,'');
  j:=40;
  setColor(darkGray);
  for n:=-320 div j to 320 div j do line(320+n*j,0,320+n*j,479);
  for n:=-240 div j to 240 div j do line(0,240+n*j,639,240+n*j);
  setColor(white);
  line(0,240,639,240); line(320,0,320,479);
  x:=-320/j; pierwotna:=0; Dx:=0.001;
  repeat
    x:=x+Dx;
    putPixel(round(x*j+320),round(-f(x)*j+240),lightBlue);
    pierwotna:=pierwotna+f(x)*Dx;
    for k:=-5 to 5 do
        putPixel(round(x*j+320),round(-pierwotna*j+240+k*j),lightRed);
  until x>320/j;
  readln; closegraph;
end.