Hello,
Why curve drawn is not that expected ?
Fabrice

\starttext
\startMPcode
     input hvdm;
     l:=2.8mm; r:=0.6; alfa:=45; beta:=0; gamma:=0;
     defineDefaultArrow (l, r, alfa, beta, gamma);
     numeric xmin, xmax, ymin, ymax;
     xmin :=-2; xmax := 4; ymax :=5 ;ymin:=-1; u := 1cm;
     pickup pencircle scaled 1pt ;
     drawarrow ((xmin,0) -- (xmax,0)) scaled u;
     drawarrow ((0,ymin) -- (0,ymax)) scaled u;
     draw tightfunction ("x", "2*(x-1)*(x-1)+2", xmin, xmax,
(xmax-xmin)/10)
     scaled u;
     setbounds currentpicture to boundingbox (((xmin,ymin) --
     (xmax,ymax)) scaled u);
\stopMPcode
\stoptext