Hi again,
I would also like to show to Bernard another plot2d option that will
make the plot nicer, and at the same time amend my last message by
including the 3rd asymptote that Aleksas plotted:
(%i1) display2d: false$
(%i2) f: t^3/(t-1)/(t+2)$
(%i3) g: (t^2-2*t)/(t-1)$
(%i4) m1: limit(g/f,t,-2)$
(%i5) m2: limit(g/f,t,1)$
(%i6) m3: limit(g/f,t,inf)$
(%i7) a1: m1*x + limit(g-m1*f,t,-2);
(%o7) -8/3
(%i8) a2: m2*x + limit(g-m2*f,t,1);
(%o8) 8/3-3*x
(%i9) a3: m3*x + limit(g-m3*f,t,inf);
(%o9) x
(%i10)
plot2d([a1,a2,a3,[parametric,f,g,[t,-20,-2.1]],[parametric,f,g,[t,-1.9,0.9]],[parametric,f,g,[t,1.1,20]]],[x,-30,20],[y,-20,10],[nticks,200],[legend,false],[color,black,black,black,blue,blue,blue]);
Of course, I made some attempts first to find some appropriate values
for x and y, and I also checked that m1, m2, and m3 gave constant
numbers, otherwise there would be no asymptotes.
Regards,
Jaime