盘点向量的相关性
(1) $\alpha_1=\left(\begin{array}{l}a \\ 1 \\ 1\end{array}\right), \alpha_2=\left(\begin{array}{c}1 \\ a \\ -1\end{array}\right), \alpha_3=\left(\begin{array}{c}1 \\ -1 \\ a\end{array}\right)$;
(2) $\alpha_1=\left(\begin{array}{l}1 \\ 2 \\ -2 \\ 1\end{array}\right), \alpha_2=\left(\begin{array}{l}0 \\ 1 \\ a \\ 1\end{array}\right), \alpha_3=\left(\begin{array}{l}2 \\ 1 \\ 2 \\ -1\end{array}\right)$.