Re: Asymptote strangeness...
- To: mathgroup at smc.vnet.net
- Subject: [mg38857] Re: Asymptote strangeness...
- From: "Allan Hayes" <hay at haystack.demon.co.uk>
- Date: Thu, 16 Jan 2003 03:20:01 -0500 (EST)
- References: <b033br$n11$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Mike, For x<0 (x + 2)/(Abs[x] - 2) is (x + 2)/(-x - 2) Which is -1 for all x not equal to -2 and is undefined at x = -2. So there is no asymptote at x=-2, and unless Plot takes a sample height at x=-2, exactly, in which case it will complain about not getting a real value, it will be quite unaware of this feature. Allan --------------------- Allan Hayes Mathematica Training and Consulting Leicester UK www.haystack.demon.co.uk hay at haystack.demon.co.uk Voice: +44 (0)116 271 4198 Fax: +44 (0)870 164 0565 "Mike Summers" <mike at miscanthus.net> wrote in message news:b033br$n11$1 at smc.vnet.net... > 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 > >