-4 2 setxrange
-2 4 setyrange

.5 .5 setquadrillagestep
quadrillage
traceaxes
axesarrow
1 xmark
1 ymark

/f {
   setxvar
   x 1 sub
   2 x mul Exp mul
} def

/f' {pop -1} def 

1.2 setlinewidth
{f} courbe

2.8 settailletangente
0 (f) tangente

/hangle 45 def
xmin 0 {f} Hachcourbe

setTimesItalic
   (O) O dltext
   (C) -3 dup f dltext
   (x ) xmax 0 dltext
   (y ) 0 ymax dltext
   (T) .5 -1.5 dltext