28.45 setxunit
90 setangle_repere
-4 6 setxrange
-6 4 setyrange
2 2 settkstep
ticks
marks
traceaxes
axesarrow
unites
/a 2 def
/b -3 def
/f {setxvar
#rpn#   2*x^2-3*x+1
} def
/k {setxvar
#rpn#   4*x-3
} def
/g {setxvar
#rpn#   3*x^2-5*x-2
} def
/l {setxvar
#rpn#   6*x-5
} def
/h {setxvar
#rpn#   -2+5*x+2*x^2
} def
/m {setxvar
#rpn#   4*x+5
} def
gsave
   bleu
   1 setlinewidth
   continu
   {f} courbe
grestore
gsave
   bleu
   1 setlinewidth
   continu
   {g} courbe
grestore
gsave
   bleu
   1 setlinewidth
   continu
   {h} courbe
grestore
setTimesItalic 
<latex>
$2x^2-3x+1$
</latex>
a dup f [1 dup] {a k 1 atan}ultexlabel
<latex>
$3x^2-5x-2$
</latex>
a dup g [1 dup] {a l 1 atan}ultexlabel
<latex>
$-2+5x+2x^2$
</latex>
b dup h [1 dup] {b m 1 atan} urtexlabel