题目内容

A为3阶方阵,且\[\left| A \right| = - 2,A = \left( {\begin{array}{*{20}{c}} {{A_1}}\\ {{A_2}}\\ {{A_3}} \end{array}} \right)\],其中`\A_1`,`\A_2`,`\A_3`分别为A的1、2、3行,则\[\left| {\begin{array}{*{20}{c}} {{A_3} - 2{A_1}}\\ {3{A_2}}\\ {{A_1}} \end{array}} \right| = \]( )

A. 3
B. 4
C. 5
D. 6

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已知`\alpha = (1,1,1)`,则`\|alpha ^Talpha|= `( )

A. -1
B. 0
C. 1
D. 2

已知`a,b,c,d,t\in R`,且向量组`\alpha _1 = (1,2, - 1,1),\alpha _2 = (2,0,t,0),\alpha _3 = (0, - 4,5, - 2)`能由`\beta_1=(1,a,1,b),\beta_2=(1,c,2,d)`线性表示,则`t=`( )

A. `1;`
B. `2;`
C. `3;`
D. `4.`

已知向量组`\alpha_1\alpha_2,\alpha_3,\alpha_4`线性无关,则向量组( )

A. `\alpha_1+\alpha_2,\alpha_2+\alpha_3,\alpha_3+\alpha_4,\alpha_4+\alpha_1`线性无关;
B. `\alpha_1-\alpha_2,\alpha_2-\alpha_3,\alpha_3-\alpha_4,\alpha_4-\alpha_1`线性无关;
C. `\alpha_1+\alpha_2,\alpha_2+\alpha_3,\alpha_3+\alpha_4,\alpha_4-\alpha_1`线性无关;
D. `\alpha_1+\alpha_2,\alpha_2+\alpha_3,\alpha_3-\alpha_4,\alpha_4-\alpha_1`线性无关。

设` A `为2阶方阵,` \alpha_1,\alpha_2 `是二维线性无关列向量,`A\alpha_1=0, A\alpha_2=2\alpha_1+\alpha_2 `,则的非零特征值为 ( )

A. `1`;
B. `2`;
C. `3`;
D. `4`。

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