Re: Vectors,Norms and assumptions
- To: mathgroup at smc.vnet.net
- Subject: [mg82786] Re: Vectors,Norms and assumptions
- From: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>
- Date: Wed, 31 Oct 2007 06:06:30 -0500 (EST)
- Organization: The Open University, Milton Keynes, UK
- References: <fg6rjo$e89$1@smc.vnet.net>
sapsi wrote: > I have a question in mathematica (actually 3). > > 1. Let v be v={av1,av2} , then Norm[v]=Sqrt[Abs[av1]^2 + Abs[av2]^2] > Q: How do indicate to mathematica that av1 and av2 belong to reals? <snip> You could use *Simplify* with the *Assumptions* option as in the following example. In[1]:= v = {av1, av2}; Norm@v Norm@v // Simplify[#, Assumptions -> Element[v, Reals]] & Out[2]= Sqrt[Abs[av1]^2 + Abs[av2]^2] Out[3]= Sqrt[av1^2 + av2^2] Regards, -- Jean-Marc