4. Let $S = \{\vec{v}_1, \vec{v}_2, \dots, \vec{v}_n\}$ be a basis for $R^n$ and $A$ be a $n \times n$ nonsingular matrix. Please show that $\{A\vec{v}_1, A\vec{v}_2, \dots, A\vec{v}_n\}$ is linear independent. (10%)
4. Let $S = \{\vec{v}_1, \vec{v}_2, \dots, \vec{v}_n\}$ be a basis for $R^n$ and $A$ be a $n \times n$ nonsingular matrix. Please show that $\{A\vec{v}_1, A\vec{v}_2, \dots, A\vec{v}_n\}$ is linear independent. (10%)