Re: Bug with Limit?

*To*: mathgroup at smc.vnet.net*Subject*: [mg73921] Re: Bug with Limit?*From*: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>*Date*: Sat, 3 Mar 2007 01:02:35 -0500 (EST)*Organization*: The Open University, Milton Keynes, UK*References*: <es91g4$34b$1@smc.vnet.net>

Sergio Miguel Terrazas Porras wrote: > Hi guys, > > I was teaching a class and was discussing discontinuous functions. > We came across f(x) = Abs(x)/x, and g(x) = 1/(x-3). > The first does not have a limit as x -> 0 and the second does not have a > limit as x -> 3. > The unilateral limits of both are different. > When I specified the direction, Mathematica 5.1 gave the correct answer. > However, when no direction was specified, Mathematica 5.1 gave (seemingly) > by default the value of de right handside limit. > > This is plain wrong, and could lead to problems, specially for a student. > Any comments? > > Thank you. > Sergio Terrazas > The following thread "Calculus: limits", among many others about the same subject (just google comp.soft-sys.math.mathematica), already contents numerous comments: http://groups.google.com/group/comp.soft-sys.math.mathematica/browse_thread/thread/35518b2c019c9fed/25c0f5767d75ef2f?lnk=gst&q=limit+helen&rnum=1#25c0f5767d75ef2f Regards, Jean-Marc