An XCas question....

[webmasterpdx]

I notice that the HP Prime CAS and XCas behave similarly (obviously) towards the following integral....
integrate(e^(-a*x),x,0,+infinity)
in that it only gives a defined answer if you run assume(RE(a)>0) beforehand, as 1/a result.

However, if using Mathematica (Wolfram Alpha) when you give it the problem:

integrate(e^(-a*x),x,0,infiinity)

it gives the result as 1/a for RE(a)>0

i.e. It figures out the conditions for a defined answer and presents them. I don't have to figure out that I need to use +infinity or RE(a)>0. The CAS system figures out the boundaries, instead of me having to know them in advance. The Wolfram Alpha system is a better system in that respect.
I'm wondering is it a big deal for it to figure that out...i.e. I'd love for our CAS system to behave that way....

Here is what I'm talking about...
http://www.wolframalpha.com/input/?i=int...,infinity)

Thx
-Donald