20 setxunit
-8 5 setxrange
-5 4 setyrange
quadrillage

gsave
   orange
   3 setlinewidth
   [xmin 0 3 sqrt neg 0] ligne
   [xmax 0 3 sqrt 0] ligne
grestore

tracerepere
2 setxmkstep
xmarks

/f {
   1 add dup mul neg 3 add
} def

{f} courbe
{-2 mul 1 sub} courbe

/fontsize 10 store

/dotscale {.8 dup} def
[3 sqrt dup neg] {dup f} apply dashpoints

setTimesItalic
   (x) xmax 0 dltext
   (y) 0 ymax dltext

<tex>
$$
   y = -x^2 -2x + 2
$$
</tex>

-3.5 dup f ultexlabel

<tex>
$\displaystyle {\phantom \int y = -2x - 1}$
</tex>

-2 3 bltexlabel