Re: Help with Nitegrate

*To*: mathgroup at smc.vnet.net*Subject*: [mg46212] Re: [mg46189] Help with Nitegrate*From*: "Sseziwa Mukasa,,(978) 536-2359" <mukasa at jeol.com>*Date*: Thu, 12 Feb 2004 07:15:41 -0500 (EST)*References*: <200402100506.AAA04053@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

On Feb 10, 2004, at 12:06 AM, Someone wrote: > I am trying to use the numerical integration function to find evaluate > this > integeral: > NIntegrate[Exp[-2.68317^2/(4* sig)]*Erfc[Sqrt[(1000 - 1)/(1000 - > sig)]*((1.07327/ > 2) + (sig - 1)/(2*0.000132817))]/(sig^(1.5)), { sig, 1, 1000}]. > > I am getting all sorts of error messages particularly that the > integral is > not numerical at some points in the interval. I've tried all the > options > possible and no success. Any ideas? There's an obvious problem at sig = 1000, Erfc's argument is undefined. You may want to replace that with the limiting value of the expression. Unfortunately Mathematica can't find one, and I'm too lazy to look into it further. Regards, Ssezi