Mathematica 9 is now available
Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2002
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2002

[Date Index] [Thread Index] [Author Index]

Search the Archive

Failures (?) in Limit[f[x,y],x->x0]

  • To: mathgroup at smc.vnet.net
  • Subject: [mg34720] Failures (?) in Limit[f[x,y],x->x0]
  • From: Jack Goldberg <jackgold at umich.edu>
  • Date: Mon, 3 Jun 2002 01:46:38 -0400 (EDT)
  • Sender: owner-wri-mathgroup at wolfram.com

Hi Group,

Consider this for starters:

(1)    	Limit[ f[x], x->0 ]  returns unmodified

as it should.

(2)  	Limit[ f[x], x->0, Analytic->True ] returns  f[0].

This is what the
help menu says should happen and it does.

Now,

(3)	Limit[ f[x,y],  x->0 ]  returns  f[0,y]  !!!!!

This is bad news for many reasons besides the obvious violation of the
definition as given in the Help.  It may be wrong if  f[x,y]  is
discontinuous at  x = 0.  By the way, you can replace  0  by any parameter
and write f as any function with 2 or more variables WHICH IS NOT
built-in.  I have not checked it using built-in functions of more than one
variable.

I hope I am missing something because my work requires that Limit obey the
rules I thought I understood by readin  ? Limit .  As always, I am
grateful for your thoughts and comments.

Jack




  • Prev by Date: Cut and paste: General rules ?
  • Next by Date: RE: eliminate some characters inside a file
  • Previous by thread: Re: Cut and paste: General rules ?
  • Next by thread: How can solue the inequation system in mathematica