25 setxunit 7.5 setborder 90 setangle_repere -2 5 setxrange -3 5 setyrange 1 1 settkstep .5 .5 setsubtkstep 2 2 setmkstep ticks subticks marks traceaxes axesarrow 1.75 setlinewidth continu bleu /X {settvar 2 t 3 exp mul 3 t 2 exp mul add } def /Y {settvar 3 t 4 exp mul 4 t 3 exp mul add } def 3 neg 3 {X} {Y} Courbeparam