Re: Re: Mathematica Integration help

*To*: mathgroup at smc.vnet.net*Subject*: [mg86178] Re: [mg86156] Re: Mathematica Integration help*From*: Daniel Lichtblau <danl at wolfram.com>*Date*: Wed, 5 Mar 2008 03:38:24 -0500 (EST)*References*: <fqetdm$jjs$1@smc.vnet.net> <fqghfq$f5c$1@smc.vnet.net> <200803040707.CAA22493@smc.vnet.net>

Francogrex wrote: > On Mar 3, 10:47 am, Jens-Peer Kuska <ku... at informatik.uni-leipzig.de> > wrote: > >>look what happens when you compute from: >>res = Integrate[ >> Product[1/(E^((Subscript[x, i] - \[Mu])^2/(2*\[Sigma]^2))* >> Sqrt[2*Pi*\[Sigma]^2]), {i, 1, n}], \[Mu]] >> >>D[res,\[Mu]] >> >>and see that the result is *not* >> >>Product[1/(E^((Subscript[x, i] - \[Mu])^2/(2*\[Sigma]^2))* >> Sqrt[2*Pi*\[Sigma]^2]), {i, 1, n}] >> >>this obvious a bug. > > > The result is: > > (1/(E^((\[Mu] - Subscript[x, i])^2/(2*\[Sigma]^2))*Sqrt[\[Sigma]^2]))^ > n/(2*Pi)^(n/2) > > Do you mean that it cannot reconstitute the product? > He means that it is a bug. Specifically, the indefinite integral produced as 'res' is garbage. This is the same bug that was reported to comp.soft-sys.math.mathematica by David Cantrell around 6 weeks ago: http://forums.wolfram.com/mathgroup/archive/2008/Jan/msg00341.html This has been fixed in the development kernel. Daniel Lichtblau Wolfram Research

**References**:**Re: Mathematica Integration help***From:*Francogrex <franco@grex.org>