試題詳解

4. (5%) Let A be an m by n matrix. Which statement is TRUE?
(A) The null space of A is a subspace of the column space of A^T
(B) The dimension of the null space of A plus the dimension of the row space of A is
(C) The null space of A^T equals column space of A
(D) The column space of A is orthogonal to the row space of A^T
(E) The direct sum of the row space of A and the null space of A^T is R^m