assumptions question
- To: mathgroup at smc.vnet.net
- Subject: [mg21893] assumptions question
- From: Peter Jay Salzman <psalzman at landau.ucdavis.edu>
- Date: Wed, 2 Feb 2000 22:54:50 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
Dear all,
I have an integral whose output contains things which look like:
(Sign[m] - I Sign[h t])
Since m is mass, h is hbar and t > 0, I placed placed a:
Assumptions -> {Sign[m] > 0, Sign[t h] > 0}
inside the Integrate[ ] command.
Integrate[ Sin[k r]/(k r) * Exp[-I*(h k)^2 t /(2 m h)],
Assumptions-> {Sign[m] > 0, Sign[t h] > 0},
{k, 0, Infinity}]
It seems to be ignoring me. The Sign[m]'s keep showing up. Is there a way
to tell Mathematica that m is always positive? I *thought* this was the way of
doing it...
pete