28.4527 setxunit %% 10 mm
14.2263 setyunit %% 5 mm

/arrowscale {.6 dup} def
/dotscale {.8 dup} def
-1 12.9 setyrange
-3 2.9 setxrange
tracerepere
xmarks

/f {setxvar
#rpn# 2*x^3 + 3*x^2 +6
} def

/g {setxvar
#rpn# 4*x^2 +4*x+3
} def

/A {-1.5 dup f} def
/B {1 dup f} def
/C {-1 dup f} def
/D {-.5 dup g} def

.9 setlinewidth
-2 1.2 {f} Courbe
bleu
-2 1.2 {g} Courbe
noir
/hwidth .5 def
/hstep 4 def
-1.5 1 {f} {g} Hachcourbes

[A B] {xdashpoint} papply
[C D] {point} papply

setTimesItalic
   (O) O dltext
   (A) A cltext
   (B) B crtext
   (C) C uctext
   (D) D dctext
   (C) -2 dup g (-5 0) cltext
setTimes 
   (2) indice
setTimesItalic
   (C) -2 dup f (-5 0) cltext
setTimes 
   (1) indice

#tex# $\vec \jmath $
0 .5 cltexlabel
#tex# $\vec \imath $
.5 0 dctexlabel