Actually, no. :) I subbed

into the

integral to get it into the form I posted.

As to the "largeness" argument, I am assuming a function that approaches a constant value at either infinity (ie I am assuming

exists) and since I'm assuming f(x) is a

function I am also assuming no discontinuities. (Perhaps I wasn't clear enough about that in my first post.) I believe (please correct me if I'm wrong) that guarentees the existence of the integral. If not then I am simply forced to add the assumption that the integral does exist and I'll work out later what restrictions that puts on the Physics.

-Dan