-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