Re: Simplifying with positive constants
- To: mathgroup at smc.vnet.net
- Subject: [mg26081] Re: [mg26062] Simplifying with positive constants
- From: Andrzej Kozlowski <andrzej at tuins.ac.jp>
- Date: Tue, 28 Nov 2000 01:55:28 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
on 00.11.22 3:55 PM, djago at my-deja.com at djago at my-deja.com wrote: > I'm trying to calculate some results and when I evaluate them I get: > 1/2(r*a-a*d-Sqrt[4*r*a^2*d+(-r*a+a*d)^2] > > I know that this is a complicated way of saying: > r*a > > but Mathematica (3.0) doesn't seems to get the idea... > > I've tried with FullSimplify and so on... but Mathematica won't let a > go out of the Sqrt function. Maybe If I could tell Mathematica that a, > r and d are real and positive values... > > Can somebody give me a hint of how to do this??? > > Thx! > > > Sent via Deja.com http://www.deja.com/ > Before you buy. > > This sort of thing is much easier to do in 4.0. Still, 3.0 can also manage it (just about): In[13]:= 1/2(r*a - a*d - Sqrt[4*r*a^2*d + (-r*a + a*d)^2]) // Simplify // PowerExpand // Simplify Out[13]= -a d -- Andrzej Kozlowski Toyama International University JAPAN http://platon.c.u-tokyo.ac.jp/andrzej/ http://sigma.tuins.ac.jp/