Question

Determine if the described set is a subspace. Assume a, b, and c are real numbers. The subset of R3 consisting of vectors of the form [a b c] , where at most one of a , b and c is non 0.

The set is a subspace.
The set is not a subspace.
If so, give a proof. If not, explain why not.

Answer 1

Not a subspace

Explanation:

(4,0,0) and (0,4,0) are vectors in R3 with zero or one entries being nonzero, but their sum, (4,4,0) has two nonzero entries.