Re: Why can't Mathematica tell when something is algebraically zero?
- To: mathgroup at smc.vnet.net
- Subject: [mg108146] Re: Why can't Mathematica tell when something is algebraically zero?
- From: "Nasser M. Abbasi" <nma at 12000.org>
- Date: Tue, 9 Mar 2010 06:23:02 -0500 (EST)
- References: <hn2ltj$3kt$1@smc.vnet.net>
"mmdanziger" <mmdanziger at gmail.com> wrote in message news:hn2ltj$3kt$1 at smc.vnet.net... > This isn't the first time that I've encountered something like this in > Mathematica but in my calculations I got a term like this: > > r^2 Sqrt[(r^3 + r + 2)/r] - Sqrt[r^3 (r^3 + r + 2)] > > Which is obviously identically zero. For some reason Simplify or even > FullSimplify can't figure this out. hi; try this: In[5]:= f=r^2 Sqrt[(r^3+r+2)/r]-Sqrt[r^3 (r^3+r+2)]; Assuming[r>0,Simplify[f]] Out[6]= 0 --Nasser