Strange results of Integrate

*To*: mathgroup at smc.vnet.net*Subject*: [mg92874] Strange results of Integrate*From*: osepsi <sepsi.ors at gmail.com>*Date*: Thu, 16 Oct 2008 05:05:55 -0400 (EDT)

Dear Group, I wanted to solve the following integral: Integrate[Exp[I*k*Sqrt[x^2+y^2+z^2]]/Sqrt[x^2+y^2+z^2],{x,-a,a},{y,- b,b},{z,-c,c}] The result was 0. (It is wrong solution...) Replacing b and c with a gives back the integral unevaluated. With NIntegrate I have the result, but with some warning messages. Questions: 1. Why gives Mathematica the wrong answer for the first formula? 2. Does anyone know the right method (Method->...) for numerical integration of this type of integral. Thanks, =D6rs