DISCONTINUITIES IN A CURVE



On 10/31/2012 09:36 AM, Rupert Swarbrick wrote:
> Bernard Luce was having some trouble posting a question to the list. I'm
> including the contents here.
>
>
> DISCONTINUITIES IN A CURVE
>
> A parametric curve displays 2 cases of discontinuity in the interval
> chosen (t= 1 and t = - 2) (see command below). However the infinite
> branches are unexpectedly linked. So, two questions :
>
> 1? is there any option to draw properly the curve and display the
>     discontinuities ?
I suggest that you remove the two discontinuities (at t=-2 and t=1) from 
the domain, like this:

(%i1) f: t^3/(t-1)/(t+2)$

(%i2) g: (t^2-2*t)/(t-1)$

(%i3) 
plot2d([[parametric,f,g,[t,-20,-2.1]],[parametric,f,g,[t,-1.9,0.9]],[parametric,f,g,[t,1.1,20]]],[nticks,200],[legend,false]);

>
> 2? Might you provide the main commands in the ASYMPA package to compute
>     the asymptotes and draw them together with the graph as well ?
I'm not familiar with ASYMPA, but since it sounds interesting to me, I 
will investigate it and if I come up with some ideas will let you know.

Best regards,
Jaime