Let A be a 4 by 3 matrix, and r(A)=2, and B is an invertible matrix, then r(AB)=______
Let A be a 4 by 3 matrix, and r(A)=2, and B is an invertible matrix, then r(AB)=______
用R语言创建一个两行三列,1到6共6个数值的矩阵,正确的代码为( ) A: matrix(1:6,<br/>ncol=3, nrow=2) B: matrix(2,<br/>3,1:6 ) C: matrix(1:6,<br/>col=3, row=2) D: matrix(1:6,<br/>3:2)
用R语言创建一个两行三列,1到6共6个数值的矩阵,正确的代码为( ) A: matrix(1:6,<br/>ncol=3, nrow=2) B: matrix(2,<br/>3,1:6 ) C: matrix(1:6,<br/>col=3, row=2) D: matrix(1:6,<br/>3:2)
Let A be a 4×4 matrix, the determinant of A is 1/3, and [img=21x20]1803c4e4937ebc3.png[/img] the adjoint matrix of A, then [img=115x27]1803c4e49b725a2.png[/img]=________. A: 1 B: 3 C: 6 D: 9
Let A be a 4×4 matrix, the determinant of A is 1/3, and [img=21x20]1803c4e4937ebc3.png[/img] the adjoint matrix of A, then [img=115x27]1803c4e49b725a2.png[/img]=________. A: 1 B: 3 C: 6 D: 9
动画对象的()方法表示一组动画完成。可以在一组动画中调用任意多个动画方法,一组动画中的所有动画会同时开始,一组动画完成后才会进行下一组动画。 A: matrix3d() B: step(Objectobject) C: export() D: matrix()
动画对象的()方法表示一组动画完成。可以在一组动画中调用任意多个动画方法,一组动画中的所有动画会同时开始,一组动画完成后才会进行下一组动画。 A: matrix3d() B: step(Objectobject) C: export() D: matrix()
If A is a 3×3 matrix and a1 +2a2 −a3 = 0, then A must be singular. A: 正确 B: 错误
If A is a 3×3 matrix and a1 +2a2 −a3 = 0, then A must be singular. A: 正确 B: 错误
After excuting the statement "[X,D]=eig(A)", D is（ ）. A: a scalar matrix B: an identity matrix C: a triangular matrix D: a diagonal matrix
After excuting the statement "[X,D]=eig(A)", D is（ ）. A: a scalar matrix B: an identity matrix C: a triangular matrix D: a diagonal matrix
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.
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.
将\(f(x)=e^x\)展开成\((x-3)\)的幂级数为( )。 A: \(\sum\limits_{n = 0}^\infty { { { { {(x - 3)}^n}} \over {n!}}} \matrix{ {} & {} \cr } ( - 1, 1)\) B: \({e^3}\sum\limits_{n = 0}^\infty { { { { {(x - 3)}^n}} \over {n!}}} \matrix{ {} & {} \cr } ( - 1, 1)\) C: \(\sum\limits_{n = 0}^\infty { { { { {(x - 3)}^n}} \over {n!}}} \matrix{ {} & {} \cr } ( - \infty , + \infty )\) D: \({e^3}\sum\limits_{n = 0}^\infty { { { { {(x - 3)}^n}} \over {n!}}} \matrix{ {} & {} \cr } ( - \infty , + \infty )\)
将\(f(x)=e^x\)展开成\((x-3)\)的幂级数为( )。 A: \(\sum\limits_{n = 0}^\infty { { { { {(x - 3)}^n}} \over {n!}}} \matrix{ {} & {} \cr } ( - 1, 1)\) B: \({e^3}\sum\limits_{n = 0}^\infty { { { { {(x - 3)}^n}} \over {n!}}} \matrix{ {} & {} \cr } ( - 1, 1)\) C: \(\sum\limits_{n = 0}^\infty { { { { {(x - 3)}^n}} \over {n!}}} \matrix{ {} & {} \cr } ( - \infty , + \infty )\) D: \({e^3}\sum\limits_{n = 0}^\infty { { { { {(x - 3)}^n}} \over {n!}}} \matrix{ {} & {} \cr } ( - \infty , + \infty )\)
【多选题】执行下列哪些选项中的语句后能得到如下矩阵? 1 1 1 1 1 2 2 2 2 2 3 3 3 3 3 4 4 4 4 4 A. > matrix(c(1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4), nrow=4, ncol=5) B. > matrix(rep(1:4, 5), nrow=4) C. > matrix(rep(1:4, each=5), nrow=4, byrow=TRUE) D. > matrix(1:4, nrow=4, ncol=5)
【多选题】执行下列哪些选项中的语句后能得到如下矩阵? 1 1 1 1 1 2 2 2 2 2 3 3 3 3 3 4 4 4 4 4 A. > matrix(c(1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4), nrow=4, ncol=5) B. > matrix(rep(1:4, 5), nrow=4) C. > matrix(rep(1:4, each=5), nrow=4, byrow=TRUE) D. > matrix(1:4, nrow=4, ncol=5)
设矩阵\(A = \left( {\matrix{ \matrix{ x \cr 0 \cr y \cr} & \matrix{ 0 \cr 2 \cr 0 \cr} & \matrix{ y \cr 0 \cr - 2 \cr} \cr } } \right)\)的一个特征值为\(-3\)，且\(A\)的三个特征值之积为\(-12\)，则\(x =\)______
设矩阵\(A = \left( {\matrix{ \matrix{ x \cr 0 \cr y \cr} & \matrix{ 0 \cr 2 \cr 0 \cr} & \matrix{ y \cr 0 \cr - 2 \cr} \cr } } \right)\)的一个特征值为\(-3\)，且\(A\)的三个特征值之积为\(-12\)，则\(x =\)______