题目内容

设`\A`是`\m \times n`矩阵,且秩`\R(A) = m`,若增加矩阵`\A`列数,则`\A`的秩可能增加。矩阵方程`\XA = B`,其中\[A = \left[ {\begin{array}{*{20}{c}} 2&1&{ - 1}\\ 2&1&0\\ 1&{ - 1}&1 \end{array}} \right],B = \left[ {\begin{array}{*{20}{c}} 1&{ - 1}&3\\ 4&3&2 \end{array}} \right]\],则`\X=` ( )

A. \[\left[ {\begin{array}{*{20}{c}}{ - 2}&1&1\\{ - \frac{8}{3}}&5&{ - \frac{2}{3}}\end{array}} \right]\]
B. \[\left[ {\begin{array}{*{20}{c}}{ - 2}&2&1\\{ - \frac{8}{3}}&5&{ - \frac{2}{3}}\end{array}} \right]\]
C. \[\left[ {\begin{array}{*{20}{c}}1&2&1\\{ - \frac{8}{5}}&5&{ - \frac{2}{3}}\end{array}} \right]\]
D. \[\left[ {\begin{array}{*{20}{c}}{ - 2}&1&1\\{ - \frac{8}{5}}&5&{ - \frac{2}{3}}\end{array}} \right]\]

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若\[A = \left( {\begin{array}{*{20}{c}} {{a_1}}&{{b_1}}\\ {{a_2}}&{{b_2}}\\ {{a_3}}&{{b_3}} \end{array}} \right),B = \left( {\begin{array}{*{20}{c}} {{a_1}}&{{b_1}}&{{c_1}}\\ {{a_2}}&{{b_2}}&{{c_2}}\\ {{a_3}}&{{b_3}}&{{c_3}} \end{array}} \right)\],且三条不同直线`\a_ix + b_iy + c_i = 0(i = 1,2,3)`相交于一点,则矩阵`\A,B`的秩满足 ( )

A. `\R(A)=R(B)=2`
B. `\R(A)=R(B)=0`
C. `\R(A)=2R(B)=2`
D. `\2R(A)=R(B)=2`

设`\A`为2017阶矩阵,且满足`\A^T=-A`,则`\|A|=` ( )

A. 0
B. 1
C. 2
D. \[\frac{1}{2}\]

设`\A`是方阵,如有矩阵关系式`\AB=AC`,则必有 ( )

A. `\A=O`
B. `\B \ne C`时`\A=O`
C. `\A \ne O`时`\B = C`
D. `\|A| \ne 0`时`\B = C`

设有任意两个`n`维向量组`\alpha_1,\alpha_2,\cdots,\alpha_m`和`\beta_1,\beta_2,\cdots,\beta_m`. 若存在两组不全为零的数 `\lambda_1,\lambda_2,\cdots,\lambda_m`和`k_1,k_2,\cdots,k_m` 使 `(\lambda_1+k_1)\alpha_1+(\lambda_2+k_2)\alpha_2+\cdots+(\lambda_m+k_m)\alpha_m +(\lambda_1-k_1)\beta_1+(\lambda_2-k_2)\beta_2+\cdots+(\lambda_m-k_m)\beta_m=0`,则( )

A. ` \alpha_1,\alpha_2,\cdots,\alpha_m`和`\beta_1,\beta_2,\cdots,\beta_m`都线性相关;
B. ` \alpha_1,\alpha_2,\cdots,\alpha_m`和`\beta_1,\beta_2,\cdots,\beta_m`都线性无关;
C. ` \alpha_1+\beta_1,\alpha_2+\beta_2,\cdots,\alpha_m+\beta_m,\alpha_1-\beta_1,\alpha_2-\beta_2,\cdots,\alpha_m-\beta_m`线性无关;
D. ` \alpha_1+\beta_1,\alpha_2+\beta_2,\cdots,\alpha_m+\beta_m,\alpha_1-\beta_1,\alpha_2-\beta_2,\cdots,\alpha_m-\beta_m`线性相关。

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