Re: Integrate returns 0
- To: mathgroup at smc.vnet.net
- Subject: [mg23957] Re: [mg23888] Integrate returns 0
- From: Andre Heinemann <andre at aflo4.ifw-dresden.de>
- Date: Sun, 18 Jun 2000 03:00:41 -0400 (EDT)
- Organization: IFW
- Sender: owner-wri-mathgroup at wolfram.com
n a message dated 6/15/2000 1:13:26 AM, felix.klee at inka.de writes:
>when I define the function
> f[x_,n_]:=D[Exp[-x^2],{x,n}]^2
>and execute
> Integrate[f[x,n],{x,-Infinity,Infinity}]
>the result is
> 0
>
>However this is not correct for all parameters n since
> Integrate[f[x,1],{x,-Infinity,Infinity}]
>returns
> Sqrt[Pi/2]
>
>Is this a bug in Mathematica or am I doing something wrong?
>
This is a bug, the answer should be:
\!\(2\^\(\(-\(1\/2\)\) + n\)\ Gamma[1\/2 + n]\)
----------------------------------
Intf[n_?IntegerQ] :=
\!\(2\^\(\(-\(1\/2\)\) + n\)\ Gamma[1\/2 + n]\)
compare the output of
Table[Intf[n], {n, 0, 10}]
with Bob Hanlon's answer in [mg23915]
Andre