#définition de quelques variables
	xmin=-6.
	xmax=6.
	ymin=-4.
	ymax=4.
 
	xdec=0.25
	ydec=0.25
	pasx=1.0
	pasy=1.0
 
#initialisation du terminal
reset
set term x11
unset autoscale
set xr [xmin:xmax]
set yr [ymin:ymax]
 
#options
unset border
unset label
unset xtics
unset ytics
 
set title "fonction tangente"
 
#les axes
set arrow 3 from  xmin,0 to xmax,0,3 lt -1 lw 0.5
set arrow 4 from  0,ymin to 0,ymax,3 lt -1 lw 0.5
 
#l'origine
set label "0" at xdec/2, -ydec
 
set label "x" at xmax - pasx, -ydec
set label "y" at -xdec, ymax - pasy/3
 
set label "1" at pasx, -ydec
set label "1" at -3*xdec/2, pasy
set label "-1" at -3*xdec/2, -pasy
 
set arrow from  1, -ydec/2 to  1, ydec/2 nohead lt -1
 
set arrow from  1.57, -ydec/2 to  1.57, ydec/2 nohead lt -1
set label "\34/2" at 1.57, -ydec center
 
set arrow from  -1.57, -ydec/2 to  -1.57, ydec/2 nohead lt -1
set label "-\34/2" at -1.57, -ydec center
 
set arrow from  3.1415, -ydec/2 to  3.1415, ydec/2 nohead lt -1
set label "\34" at 3.1415, -ydec center
 
set arrow from  -3.1415, -ydec/2 to  -3.1415, ydec/2 nohead lt -1
set label "-\34" at -3.1415, -ydec center
 
set arrow from  0, 0  to pasx, pasx lt 1 
set arrow from  0, 0 to  -pasx, -pasx lt 1 
 
set arrow from  -xdec/3, 1 to  xdec/3, 1 nohead lt -1 
set arrow from  -xdec/3, -1 to  xdec/3, -1 nohead lt -1 
 
set arrow from  -1.57, ymax to  -1.57, ymin nohead lt 0
set arrow from  1.57, ymax to  1.57, ymin nohead lt 0
 
plot tan(x) title "tan" w l lt 3 lw 2
 
pause -1 "maintenant va créer un fichier au format png appuyer sur entrée"
 
set term png
set out "exemple2.png"
rep
set out
set term x11
pause -1 "touche entrée pour sortir"