Change of variables in integration

*To*: mathgroup at smc.vnet.net*Subject*: [mg28266] Change of variables in integration*From*: "Loren Dill" <lorendill at mediaone.net>*Date*: Fri, 6 Apr 2001 01:53:17 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

Hi, Is there a simple way to perform a change of variables when integrating in a symbolic form? I'm writing a paper, and would like to express certain results in an unevaluated dimensionless form even though I started in a dimensional form. I know I can check things by hand, but would prefer Mathematica to do the work for me. Here is a sample double integration I want expressed in dimensionless form: Integrate[ E^(-y u/d) p[x],{x,0,-a},{y,0,b}] Here, x, y, a, b, p, u, and d are all dimensional. I want to define new dimensionless variables and parameters as follows: xh=x/a yh=y/b ph[xh]=p[xh a]/p0 pe=b u/d Here, p0 has the same dimensions as p, and pe is a dimensionless parameter. Regards, Loren Dill