Program wkleslosc_wypuklosc;
{$N+}
uses Graph;
var karta,tryb,n,siatka,j,kolor:integer;
    x,y,dx,y1,y2,y3,xpp:extended;
function f(x:extended):extended;
begin
  f:=x*x/(2*x*x-x-2);
end;
begin
  karta:=detect; initGraph(karta,tryb,'c:\tp\bgi');
  j:=20;
  setColor(darkGray);
  for n:=-320 div j to 320 div j do line(n*j+320,0,n*j+320,479);
  for n:=-240 div j to 240 div j do line(0,n*j+240,639,n*j+240);
  setColor(white); line(0,240,639,240); line(320,0,320,479);
  x:=-320/j;  Dx:=0.00025;
  repeat
    x:=x+Dx;
    y:=f(x);
    y1:=f(x+Dx);
    y2:=f(x+2*Dx);
    y3:=f(x+3*Dx);
    if y1-y>y2-y1 then kolor:=yellow else kolor:=lightRed;
    xpp:=(2*x+3*Dx)/2;
    if abs(y)<240/j then putPixel(round(xpp*j+320),round(-f(xpp)*j+240),kolor);
    if (((y2-y1<y1-y) and (y2-y1<y3-y2)) or ((y2-y1>y1-y) and (y2-y1>y3-y2))) and
       (abs(y)<240/j) and (abs(y1)<240/j) and (abs(y2)<240/j) and (abs(y3)<240/j) then
       writeLn('xpp=',xpp:18:14,',  ypp=',f(xpp):18:14);

  until x>320/j;
  readln; closeGraph;
end.