Re: Asymptote strangeness...
- To: mathgroup at smc.vnet.net
- Subject: [mg38871] Re: Asymptote strangeness...
- From: "Gareth J. Russell" <gjr2008 at columbia.edu>
- Date: Thu, 16 Jan 2003 03:21:40 -0500 (EST)
- Organization: Columbia University
- References: <b033br$n11$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
In <b033br$n11$1 at smc.vnet.net> Mike Summers wrote:
> It seems to me that this:
>
> f[x] = (x + 2)/(Abs[x] - 2)
>
> should have asymptotes at 2 & -2.
>
> Plot[Evaluate[f[x]], {x, -5, 5}] only shows the asymptote at 2.
>
> Suggestions?
>
> Thanks-- Mike
The value at x = -2 is a singularity, but is not asymptotic. Plot[]
works by successively subdividing a function into a finite number of
points. It's pretty good at detecting vertically asymptotic
singularities, but would not detect the other singularity unless, by
chance, one of its plot points just happened to be exactly -2.
Gareth Russell
Columbia University