Re: Is this normal for Limit?
- To: mathgroup at smc.vnet.net
- Subject: [mg82286] Re: Is this normal for Limit?
- From: "David W.Cantrell" <DWCantrell at sigmaxi.net>
- Date: Wed, 17 Oct 2007 03:53:59 -0400 (EDT)
- References: <ff1par$8nq$1@smc.vnet.net>
Michael Mandelberg <mmandelberg at comcast.net> wrote:
> I have what I would think is the following simple limit to evaluate:
>
> $Pre = Refine[#] &;
> $Assumptions = {t \[Element] Reals, k \[Element] Reals, k > 0};
>
> In[3]:= Limit[Exp[-k t], t -> Infinity]
>
> The results is:
>
> Out[3]= Limit[\[ExponentialE]^(-k t), t -> \[Infinity]]
>
> In other words Mathematica 6.0.0 punts on this. Is there any sense in
> which this limit is not well-defined?
No. And note that in version 5.2 there is no trouble:
In[4]:= Assuming[k > 0, Limit[E^(-k t), t -> Infinity]]
Out[4]= 0
David