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Re: Re: Limit bug?

  • To: mathgroup at
  • Subject: [mg65961] Re: [mg65911] Re: [mg65904] Limit bug?
  • From: "Erickson Paul-CPTP18" <Paul.Erickson at>
  • Date: Mon, 24 Apr 2006 06:02:37 -0400 (EDT)
  • Sender: owner-wri-mathgroup at
  • Thread-index: AcZm0GF3Ej5K8sXkQ/KBlpJC2J0NwAAc7WXg

An explanation? No, but ...

There appear to be a several other ways to force the evaluation, like:
Limit[x - Log[Cosh[x]], x -> â??] // FullSimplify
or noting the negative can be pulled outside, so 
-Limit[ Log[Cosh[x]] - x, x -> Infinity]

But I do find it curious since:
Limit[ Log[Cosh[x]] - x, x -> Infinity]//Trace


Simplifies to the same form (but each term negative) ...


-----Original Message-----
From: Bob Hanlon [mailto:hanlonr at] 
To: mathgroup at
Subject: [mg65961] [mg65911] Re: [mg65904] Limit bug?

I don't know why the second form does not evaluate but you can force it with TrigToExp

Limit[TrigToExp[x - Log[Cosh[x]]], x->Infinity]


Bob Hanlon

> From: "Ray Koopman" <koopman at>
To: mathgroup at
> Subject: [mg65961] [mg65911] [mg65904] Limit bug?
> Does anyone have an explanation for this?
> I was expecting Out[2] to be Log[2].
> In[1]:= Limit[ Log[Cosh[x]] - x, x -> Infinity]
> Out[1]= -Log[2]
> In[2]:= Limit[ x - Log[Cosh[x]], x -> Infinity]
> Out[2]= Limit[x-Log[Cosh[x]],x\[Rule]\[Infinity]]

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