设向量组\( {\left( {2,1,1,1} \right)^T},{\left( {2,1,a,a} \right)^T},{\left( {3,2,1,a} \right)^T},{\left( {4,3,2,1} \right)^T} \) 线性相关，且\( a \ne 1 \) ，则 \( a = \)______

2022-11-02

答案：

0.5

设\( {\alpha _1} = {\left( {1,2, - a, - 3} \right)^T},{\alpha _2} = {\left( { - 3,2,4,1} \right)^T} \)且\( \left( { { \alpha _1},{\alpha _2}} \right) = - 1 \)，则\( a = \)（） A: \( - {2 \over 3} \) B: \( - {3 \over 4} \) C: \( - {1 \over 4} \) D: \( {1 \over 2} \)
向量组\({\alpha _1} = {\left( {1,1,1} \right)^T}{\kern 1pt} ,\;{\alpha _2} = {\left( {2,3,4} \right)^T},\,{\alpha _3} = {\left( {3,2,3} \right)^T},{\alpha _4} = {\left( {4,3,4} \right)^T}\)的一个极大无关组是( ) A: \({\alpha _1}\,,{\alpha _2}\) B: \({\alpha _1}\,,{\alpha _2},{\alpha _3}\) C: \({\alpha _2},{\alpha _3}\) D: \({\alpha _1}\,{\alpha _3}\)
设\(A\)为\(n\)阶方阵,\(\left| A \right| = 2 \)，则\(\left| {\left| A \right|{A^T}} \right|=\) A: \({2^{n + 1}} \) B: \({2^{n }}\) C: \({2^{n - 1}}\) D: \(2\)
向量组\(\left( {\matrix{ { - 1} \cr 3 \cr 1 \cr } } \right),\left( {\matrix{ 2 \cr 1 \cr 0 \cr } } \right),\left( {\matrix{ 1 \cr 4 \cr 1 \cr } } \right) \)线性相关.
设\( \alpha {\rm{ = }}\left( {\matrix{ 1 \cr 0 \cr 1 \cr } } \right)\;A = \alpha {\alpha ^{T,}} \) ，则\( \left| {I - {A^n}} \right| = \) （） A: \( 1 + {2^n} \) B: \( 1 - {2^n} \) C: \( 1 + {3^n} \) D: \( 1 - {3^n} \)

0
设 \( A \)是 \( 3 \times 3 \)矩阵， \( B \)是 \( 4 \times 4 \)矩阵，且\( \left| A \right| = 1,\,\left| B \right| = - 2, \) 则\( \left| {\left| B \right|A} \right| = \) ______
1
设 \( A \)为三阶方阵，且\( \left| A \right| = 1 \) ，则 \( \left| {2{A^{ - 1}} - 3{A^*}} \right| = \) A: 1 B: -1 C: 25 D: -25
2
设\(z = \int_ { { x^2}}^y { { e^t}\sin t} dt\)，则\({z_{xx}=}\) A: \(2{e^ { { x^2}}}\left[ {\left( {1 + 2{x^2}} \right)\sin {x^2} + 2{x^2}\cos {x^2}} \right]\) B: \( - 2{e^ { { x^2}}}\left[ {\left( {1 + 2{x^2}} \right)\sin {x^2} - 2{x^2}\cos {x^2}} \right]\) C: \( - 2{e^ { { x^2}}}\left[ {\left( {1 + 2{x^2}} \right)\sin {x^2} + 2{x^2}\cos {x^2}} \right]\) D: \( - 2{e^ { { x^2}}}\left[ {\left( {1 + 2{x^2}} \right)\cos {x^2} + 2{x^2}\sin {x^2}} \right]\)
3
函数\(y = {\left( { - 2x + 1} \right)^4}\)的导数为（）. A: \( - 8{\left( { - 2x + 1} \right)^3}\) B: \(8{\left( { - 2x + 1} \right)^3}\) C: \(4{\left( { - 2x + 1} \right)^3}\) D: \(- 4{\left( { - 2x + 1} \right)^3}\)
4
设\( A,\;B \) 均为\( n \) 阶方阵，则必有（）. A: \( {(A + B)^2} = {A^2} + 2AB + {B^2} \) B: \( \left| {A + B} \right| = \left| A \right| + \left| B \right| \) C: \( \left| {AB} \right| = \left| A \right|{\kern 1pt} \left| B \right| \) D: \( {\left( {AB} \right)^{\rm T}} = {A^{\rm T}}{B^{\rm T}} \)