-4 4 setxrange
-4 2 setyrange

/f {
   dup dup	% x, x, x
   mul exch	% x^2, x
   3 sub mul 	% x^3-3x^2
   1 add
}  def

/f' {pop 0} def
/unites {} def
tracerepere
marks

[ -1 1 2 3] {dup f dashpoint} apply

2 settailletangente
0 (f) tangente
2 (f) tangente

1 setlinewidth
{f} courbe


setTimesItalic
   (O) 0 0 dltext
   (A) 0 1 urtext
   (B) 2 -3 drtext