Re: Assuming to be a real number is useless even in simple cases?
- To: mathgroup at smc.vnet.net
- Subject: [mg63951] Re: [mg63945] Assuming to be a real number is useless even in simple cases?
- From: "Erickson Paul-CPTP18" <Paul.Erickson at Motorola.com>
- Date: Wed, 25 Jan 2006 04:11:22 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
Because the function Im doesn't make assumptions (or more appropriate take $Assumptions). That is assumptions are used by Simplify, Integrate, Refine, ? Others ? , but not Im. Therefore Assuming[x\[Element]Reals, Im[x]] is not substantially different from just Im[x]. However, Simplify does take arguments, so "Assuming[x\[Element]Reals, Simplify[ Im[x] ] ] " is "0". Paul -----Original Message----- From: Roberto [mailto:roberto at pop.it] To: mathgroup at smc.vnet.net Subject: [mg63951] [mg63945] Assuming to be a real number is useless even in simple cases? In[1]:= Assuming[x\[Element]Reals, Im[x]] Out[1]= Im[x] Why it's not zero?