-6 7 setyrange
-5 6 setxrange
/f {
   1 sub dup mul 4 sub
} def

quadrillage
tracerepere
marks
1 setlinewidth
{f} courbe

<tex>
$\cal P$
</tex>
4 dup f drtexlabel

mixte
{-2 mul 2 sub} courbe

<tex>
$y = -2x-2$
</tex>
-3 4 {-2 1 atan} dctexlabel