Mathematica 9 is now available
Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2007
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2007

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

Search the Archive

Limit question

  • To: mathgroup at smc.vnet.net
  • Subject: [mg73072] Limit question
  • From: "dimitris" <dimmechan at yahoo.com>
  • Date: Thu, 1 Feb 2007 03:19:00 -0500 (EST)

Practising with the Limit command I discover the following setting

In[487]:=
(Limit[Log[z], z -> -1, Direction -> #1] & ) /@ {I, -I}

Out[487]=
{(-I)*Pi, I*Pi}

So my simple question is if it is somewhere documented in the
Mathematica Book that you can use other values than just {1,-1} for
the Direction Option. Note that

In[481]:=
Information[Direction]

>From In[481]:=
"Direction is an option for Limit. Limit[expr, x -> x0, Direction ->
1] computes the limit as x approaches x0 from smaller \
values. Limit[expr, x -> x0, Direction -> -1] computes the limit as x
approaches x0 from larger values. Direction -> Automatic \
uses Direction -> -1 except for limits at Infinity, where it is
equivalent to Direction -> 1."

>From In[481]:=
Attributes[Direction] = {Protected}

Note also that even in this link
http://support.wolfram.com/mathematica/kernel/Symbols/
in which for some Built-In functions you can find additional
information (for example
http://support.wolfram.com/mathematica/kernel/Symbols/System/
Oscillatory.html
http://support.wolfram.com/mathematica/kernel/Symbols/System/
Integrate.html )
there is no other information.

Dimitris


  • Prev by Date: Definite Integration Question
  • Next by Date: Re: sort and positon matrix element help
  • Previous by thread: Definite Integration Question
  • Next by thread: Re: Limit question