%% auteur : Peric
28.45 setxunit
/xmarkstyle {[1.3 dup] dctext} def
/ymarkstyle {[1.3 dup] ultext} def
-4.9 6.9 setxrange
-4.9 1.9 setyrange
1 1 settkstep
1 1 setmkstep
ticks
marks
traceaxes
axesarrow
unites
/a{1.5}def
/f {setxvar
#rpn#   (8*x-12)/(x^2+4)
} def
/f' {0} def
/g {setxvar
#rpn#   2*x-3
} def
/h {setxvar
#rpn#   (9/4)*(x-1)
} def
gsave
   bleu
   2 setlinewidth
   continu
   -4 6 {f} (*-*) Courbe
grestore
gsave
   noir
   1 setlinewidth
   %pointilles
   {g} courbe
-1 {f} tangente
4 {f} tangente
grestore


#latex# $y=2x+3$
 1.5 dup g [1 dup ] {2 1 atan} bleu urtexlabel

#latex# $f(x)=\frac{8x-12}{x^2+4}$
 2 -4 [a dup ]   bleu crtexlabel