Re: number types
- To: mathgroup at smc.vnet.net
- Subject: [mg21645] Re: number types
- From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
- Date: Fri, 21 Jan 2000 03:59:55 -0500 (EST)
- Organization: Universitaet Leipzig
- References: <861529$jjr@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Hi, look what the Assumptions-option ?Assumptions "Assumptions is an option for Integrate and other functions that specifies \ what assumptions be made about relations between parameters." and in Mathematica 4.0 FullSimplify[expr,Element[a,Reals]] can do for you. Hope that helps Jens Naum Phleger wrote: > > I feel sort of silly asking something that should be so clear but after > LOTS of trying I can't seem to get it right. > > How can I make Mathematica know that a variable is real or positive so that > > Conjugate[a] gives a > > Sqrt[ a^2 ] gives a > > when I evaluate integrals with a in them it doesn't give me an If statement > like > > If[ Im[a]=0, answer I want , unevaluated integral ] > > this seems like it should be easy but I nothing that I try ever works. > > Thanks for any help.