Integrate question

*To*: mathgroup at yoda.physics.unc.edu*Subject*: Integrate question*From*: Roque Donizete de Oliveira <oliveria at engin.umich.edu>*Date*: Wed, 30 Sep 92 15:10:02 -0400

I'm using Mma 1.2 on an apollo workstation. How can I coerce mma to perform Integrate[ x^l Exp[-a x],{x,0,Infinity}] where a is a real number > 0 and l=0,1,2,3,... I'm also using the Declare.m package to declare the type of some variables. This has helped for some other integrals but not integrals like the one above involving x^l. Thanks. Roque oliveria at caen.engin.umich.edu