More weird integration issues...

*To*: mathgroup at smc.vnet.net*Subject*: [mg35728] More weird integration issues...*From*: "Binesh Bannerjee" <binesh at hex21.com>*Date*: Sat, 27 Jul 2002 06:43:45 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

Hi. I'm trying to compute the 5th moment of a tweak to the normal pdf. Here's what I have: F[a_, b_, c_, d_, e_, f_, X_] := (a + b X + c X^2 + d X^3 + e X^4 + f X^5)* Exp[-(((X - m)/sd)^2)/2]/(Sqrt[2Pi]sd) The strange thing, and I'd appreciate someone shedding some light on this, is that this: \!\(Integrate[ F[p\_0, p\_1, p\_2, p\_3, p\_4, p\_5, X]*\((\((X - m)\)/sd)\)^5, {X, \(-Infinity\), Infinity}, Assumptions -> {sd > 0}]\) (I cut and pasted that it looks like it works) Anyway, THAT gives me an answer really quickly... (within 5 minutes on my box) JUST changing it from p0..5 to a,b,c,d,e,f like so: Integrate[F[a, b, c, d, e, f, X]*((X - m)/sd)^5, {X, -Infinity, Infinity}, Assumptions -> {sd > 0}] Causes mathematica to go into an infinite loop (seemingly after 6 hours). This ... sucks. How am I to know if a certain equation is solvable, if only I choose the right variables?? Binesh Bannerjee -- "For in much wisdom is much grief, and he that increaseth knowledge increaseth sorrow." -- Ecclesiastes 1:18 PGP Key: http://www.hex21.com/~binesh/binesh-public.asc SSH2 Key: http://www.hex21.com/~binesh/binesh-ssh2.pub SSH1 Key: http://www.hex21.com/~binesh/binesh-ssh1.pub OpenSSH Key: http://www.hex21.com/~binesh/binesh-openssh.pub