Solutions to Section 3.
2 Exercises
1. Determine whether the following sets form subspaces of R^2:
(a) Yes, it is a subspace.
(b) No, it is not a subspace.
(c) Yes, it is a subspace.
(d) No, it is not a subspace.
2. Determine whether the following sets form subspaces of R^3:
(a) No, it is not a subspace.
(b) Yes, it is a subspace.
(c) Yes, it is a subspace.
(d) No, it is not a subspace.
3. Determine whether the following are subspaces of R^(2x2):
(a) Yes, it is a subspace.
(b) Yes, it is a subspace.
(c) Yes, it is a subspace.
(d) No, it is not a subspace.
(e) Yes, it is a subspace.
(f) Yes, it is a subspace.
(g) No, it is not a subspace.
4. Null space of matrices (see detailed solutions).
5. Determine whether polynomial sets form subspaces of P_4:
(a) Yes, it is a subspace.
(b) No, it is not a subspace.
(c) Yes, it is a subspace.
(d) No, it is not a subspace.
6. Determine whether function sets form subspaces:
(a) Yes, it is a subspace.
(b) Yes, it is a subspace.
(c) No, it is not a subspace.
(d) Yes, it is a subspace.
(e) No, it is not a subspace.
7. C^1[a, b] is a subspace of C[a, b] -> Yes.
8. S = {B | AB = BA} is a subspace of R^(n x n) -> Yes.