Strange empty set of solutions

*To*: mathgroup at smc.vnet.net*Subject*: [mg71771] Strange empty set of solutions*From*: José Carlos Santos <jcsantos at fc.up.pt>*Date*: Tue, 28 Nov 2006 06:04:25 -0500 (EST)

Hi all, I have a certain 3 x 3 numerical matrix M. If I type Solve[M.{a,b,c}=={0,0,0},{a,b,c}] I get {{a -> 0. + 0.0410026 c, b -> 0. + 1.35294 c}} However, if I type Solve[{M.{a,b,c}=={0,0,0},a^2+b^2+c^2==1},{a,b,c}] I get the empty set. Why is that? I should get two solutions! Best regards, Jose Carlos Santos