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Re: Limit doesn't work properly

  • To: mathgroup at smc.vnet.net
  • Subject: [mg13275] Re: [mg13184] Limit doesn't work properly
  • From: Daniel Lichtblau <danl>
  • Date: Fri, 17 Jul 1998 03:18:16 -0400
  • References: <199807131142.HAA17482@smc.vnet.net.>
  • Sender: owner-wri-mathgroup at wolfram.com

One problem is that you do not specify v->Infinity. A more serious  
problem is that Limit will not at present cope well with factorials.  
A work-around would be to convert the sequence using FullSimplify.  
For example:

In[26]:= a[v_] = v!/v^v;

In[27]:= InputForm[expr = FullSimplify[a[v+1]/a[v]]] Out[27]//InputForm=
(v/(1 + v))^v

In[28]:= Limit[expr, v->Infinity]
         1
Out[28]= -
         E

Daniel Lichtblau
Wolfram Research


Begin forwarded message:

X-UIDL: bc4cde6063bae17d2c3c4f28b20ccad2 From: Alexander Kricke
<kricke at student.uni-kassel.de> To: mathgroup at smc.vnet.net
Subject: [mg13275] [mg13184] Limit doesn't work properly Organization: Universitat
Kassel

Hello,

Mathematica doesn't find the correct result as a number (1/e) of the
following sequence:

  a[v_]:=v!/v^v;
  N[Limit[a[v+1]/a[v],v->Identity];


What is the reason for this circumstance ??

Greetings from Germany

Alex


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