Vectors,Norms and assumptions

*To*: mathgroup at smc.vnet.net*Subject*: [mg82754] Vectors,Norms and assumptions*From*: sapsi <saptarshi.guha at gmail.com>*Date*: Tue, 30 Oct 2007 03:35:58 -0500 (EST)

Hello, 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? 2. On a similar note, i have n={an1,an2} a={aa1,aa2} (*an1,an2,aa1,aa2 are all reals*) x=Norm[y(n-a)] >> Sqrt[Abs[(-aa1 + an1) y]^2 + Abs[(-aa2 + an2) y]^2] Once again, how do i indicate that y ,an1,an2,aa1,aa2 are reals? Thank you for your time and help. Rgds Bveo