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500 setwidth
500 setheight
18 setfontsize
-5 5 setxrange
-5 5 setyrange
/f {
   Tan
} def
/val 3.14 2 div def
/dessin {
   tracerepere
   marks
   gsave
      bleu
      1.75 setlinewidth
      val neg val {f} Courbe
      val neg pi add val pi add {f} Courbe
      val neg pi sub val pi sub {f} Courbe
   grestore
   setTimesItalic
      (O) O drtext
      (La fonction tangente : y = ) -4.9 3.5 text
   setTimes
      (tan ) show
   setTimesItalic
      (x) show
   
} def
{dessin} relief
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