Re: Greater implies unequal?
- To: mathgroup at smc.vnet.net
- Subject: [mg75268] Re: Greater implies unequal?
- From: siewsk at bp.com
- Date: Mon, 23 Apr 2007 05:37:29 -0400 (EDT)
- References: <f0eke5$pom$1@smc.vnet.net>
On 5.2 In[1]:=Simplify[Sqrt[a] != 0, a > 0] Out[1]=True ================================ For your later query where you say > Well, I think it makes more sense that Out[50]or Out[51] were undefined... > You are not making much sense. If a<0 then a is REAL so Sqrt[a] >= 0 (* The Principle Squareroot of a real number is always zero or positive *) Therefore In[51]:= Simplify[Sqrt[a]<0,a>0 ] Out[51]= False is 100% correct. On Apr 22, 1:22 pm, anguz... at ing.uchile.cl wrote: > Hello: > I'm using Mathematica v5. Why do I get?: > > Clear[a]; Remove[a] > In[43]:= > Simplify[Sqrt[a]!=0,a>0] > > Out[43]= > Sqrt[a] != 0 > > In[46]:= > Simplify[Sqrt[2]!=0,a>0] > > Out[46]= > True > > In[47]:= > 2!=3 > > Out[47]= > True > > In[48]:= > Simplify[Sqrt[2 a]!=0,a>0] > > Out[48]= > Sqrt[a] != 0 > > Does anyone else get this? The main problem is In[43] and Out[43]. I checked > that "a" does not have a pre-defined value, or Sqrt. I also get : > > In[50]:= > Simplify[Sqrt[a]>0,a>0 ] > > Out[50]= > True > In[51]:= > Simplify[Sqrt[a]<0,a>0 ] > > Out[51]= > False > Well, I think it makes more sense that Out[50]or Out[51] were undefined... > > Atte. Andres Guzman > > ---------------------------------------------------------------- > This message was sent using IMP, the Internet Messaging Program.