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RJLiberator
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Homework Statement
S = a non-empty set of vecotrs in V
S' = set of all vectors in V which are orthogonal to every vector in S
Show S' = subspace of V
Homework Equations
Subspace requirements.
1. 0 vector is there
2. Closure under addition
3. Closure under scalar multiplication
The Attempt at a Solution
1. 0 is held within S' by definition here
2. Let v and v' exist within S' and let s exist within S.
<v+v',s>=<v,s>+<v',s> = 0+0 =0 which is what we want since
<v,s>=0 and <v',s>=0.
3. if x is a scalar, then <xv,s> = x<v,s> =x*0 = 0
therefore we have satisfied all the necessary requirements and have shown that S' is a subspace of V.
Question: In my notes, the instructor lists a fourth requirement, namely If v exists within S, S a subspace, then -v exists within s.
Must I prove this as well?