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

Re: wrong limit ? (3)

  • To: mathgroup at smc.vnet.net
  • Subject: [mg76761] Re: wrong limit ? (3)
  • From: dimitris <dimmechan at yahoo.com>
  • Date: Sun, 27 May 2007 04:46:53 -0400 (EDT)
  • References: <f38tdj$ish$1@smc.vnet.net>

An asymptotic expansion

In[1]:=
AsymExp1[f_, {x_, x0_, n_}] := Series[TrigToExp[f] /. E^((m_.)*x) :>
y^m//Simplify, {y, x0, n}] /. y -> Exp[x]

In[2]:=
AsymExp1[Coth[x], {x, Infinity, 10}]

Out[2]=
SeriesData[E^x, Infinity, {1, 0, 2, 0, 2, 0, 2, 0, 2, 0, 2}, 0, 11, 1]

Dimitris

 /  ventu       :
> Hi !
> Here's my problem (mathematica 5.0,5.1,5.2):
>
> Limit[Coth[xB], B -> +Infinity]
>
> it doesn't understand.
> mmh. ok I try then:
>
> Limit[Coth[x B], B -> +Infinity, Assumptions ->  Im[x] == 0]
>
> 1
>
> WRONG ! In fact:
>
> Limit[Coth[x B], B -> +Infinity, Assumptions ->  Im[x] == 0 && Re[x] <
> 0]
>
> -1
>
> Indeed the correct result should be sign(x). And I couldn't find a way
> to get it right.
> Do I mistake something?
>
> Thank you in advance,
>
> Davide



  • Prev by Date: Re: Running math in shell with notebook as output
  • Next by Date: Re: wrong limit ? (2)
  • Previous by thread: Re: Mathematica V6. ComplexMap
  • Next by thread: Re: wrong limit ? (2)