Integration with non-numeric parameters

*To*: mathgroup at smc.vnet.net*Subject*: [mg79759] Integration with non-numeric parameters*From*: ingramfinance at gmail.com*Date*: Fri, 3 Aug 2007 06:36:31 -0400 (EDT)

When I use Mathematica to solve the following y=x1/(2*sigma^2*t) Integrate[y, {t, .5, 1}] I get the following answer: (0.34657*x1/sigma^2) OK, so far, so good. It appears that I can generate an answer with a non-numeric parameter. Note that I am looking for an answer in terms of x1. But when I try q=Exp[-(x1-t)^2/2*sigma^2*t] Integrate[q, {t, .5,1}] Now Mathematica does not solve this integral, it just repeats the command I am trying to get an expression in terms of x1. Why do I get a statement like this instead of an answer? There is something about the functional form of the integrand that is causing the problem, I just don't know what it is. Any help you can give me is much appreciated!