Re: Integration Problem

*To*: mathgroup at smc.vnet.net*Subject*: [mg126369] Re: Integration Problem*From*: Bill Rowe <readnews at sbcglobal.net>*Date*: Fri, 4 May 2012 06:25:55 -0400 (EDT)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com

On 5/3/12 at 4:34 AM, michael.musheghian at gmail.com (Michael Musheghian) wrote: >I found that evaluation of this 2 integrals yield a bit different >result. What could be the reason? >Integrate[E^(-1/10 ((1 + r2z)^2)), {r2z, -Infinity, Infinity}] >Integrate[E^(-0.1 ((1 + r2z)^2)), {r2z, -Infinity, Infinity}] The first gives an exact result, the second a numerical approximation. The small complex component of In[2]:= Integrate[E^(-0.1 ((1 + r2z)^2)), {r2z, -Infinity, Infinity}] Out[2]= 5.60499 -2.03152*10^-16 I is the result of small errors introduced by imprecise values. Do In[3]:= Chop@ Integrate[E^(-0.1 ((1 + r2z)^2)), {r2z, -Infinity, Infinity}] Out[3]= 5.60499 to get rid of it.