題組內容
2 Let $A, B \in M_{n \times n}(\mathbb{R})$.
b. (10) Show that \( \operatorname{rank}(A^{\top}A) = \operatorname{rank}(A) \).
2 Let $A, B \in M_{n \times n}(\mathbb{R})$.
b. (10) Show that \( \operatorname{rank}(A^{\top}A) = \operatorname{rank}(A) \).