Re: Intelligent handling of Infinity in Limits
- To: mathgroup at smc.vnet.net
- Subject: [mg7645] Re: [mg7622] Intelligent handling of Infinity in Limits
- From: jpk at max.mpae.gwdg.de
- Date: Tue, 24 Jun 1997 03:36:08 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
Hi Peter,
> i was trying to do Integrate[ r^2 Exp[-a r^2], {r,0,Infty}] but MMA
> couldn't simplify a term which clearly was zero.
Look tin "The Book" -- every Mma identifyer is a full (!) english word
starting with a capital, so You have to type Infinity instead of the TeX
abbrevation \infty than all works fine :
In[12]:=
Integrate[ r^2 Exp[-a r^2], {r,0,Infinity}]//InputForm
Out[12]//InputForm=
If[Re[a] > 0, Sqrt[Pi]/(4*a^(3/2)),
Integrate[r^2/E^(a*r^2),
{r, 0, Infinity}]]
>
> next i tried integrating over {r,0,r} and then took the limit as r->Infty.
>
Again Infinity !
Hope that helps
Jens