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