单选题 20/20 (5分)设overrightarrow(alpha_{1)}=(1,-1,2,-1),overrightarrow(alpha_{2)}=(-2,2,3,2),overrightarrow(alpha_{3)},试判断=(1,2,0,-1),overrightarrow(alpha_{4)}=(1,0,0,1)向量组overrightarrow(alpha_{1)},overrightarrow(alpha_{2)},overrightarrow(alpha_{3)},overrightarrow(alpha_{4)}是否为正交向量组.A. 是B. 不是

单选题 20/20 (5分) 设$\overrightarrow{\alpha_{1}}=(1,-1,2,-1),\overrightarrow{\alpha_{2}}=(-2,2,3,2),\overrightarrow{\alpha_{3}},$试判断 $=(1,2,0,-1),\overrightarrow{\alpha_{4}}=(1,0,0,1)$ 向量组$\overrightarrow{\alpha_{1}},\overrightarrow{\alpha_{2}},\overrightarrow{\alpha_{3}},\overrightarrow{\alpha_{4}}$是否为正交向量组.

A. 是

B. 不是