Solving double integral without Error function

*To*: mathgroup at smc.vnet.net*Subject*: [mg57683] Solving double integral without Error function*From*: "Xavier Brusset" <brusset at poms.ucl.ac.be>*Date*: Sat, 4 Jun 2005 03:04:30 -0400 (EDT)*Organization*: Universite Catholique de Louvain*Reply-to*: brusset at poms.ucl.ac.be*Sender*: owner-wri-mathgroup at wolfram.com

Hi, I have to solve this double integral: Phi[ q_ ]=Integrate[Integrate[y(x-q)f[x,y],{x,0,q}],{y,2,15}] where f[ x_ , y_ ]=1/(2 Pi Sqrt[27])Exp{-1/54 [4 x^2 - 6yx - 50x + 9y^2 -30 y + 325]} Mathematica 5.1 on windows fumbles a lot and finally stops giving an answer in q but using the Error function (I am using the Statistics Continuous distributions module). The problem with the Error function is that when I combine this function Phi into another equation, I can't find a root in q. Which function of Mathematica should I use which circumvents the Error function in solving the double integral? Or, alternately, which root finding function could I use to find even a numeric instance of q? Thank you. To send a mail take the _ and * out. -- Xavier brusset_*_*_*@_*_*_ poms.ucl.ac.be PhD student Université Catholique de Louvain Belgium