${\rm var}(X)=\,$ ${\bf E}[X]=\,$ ${\bf P}(X=3)=\,$ ${\bf P}(X=-2)=\,$ ${\bf P}(X=1)=\,$ ${\bf P}(X=0)=\,$______
${\rm var}(X)=\,$ ${\bf E}[X]=\,$ ${\bf P}(X=3)=\,$ ${\bf P}(X=-2)=\,$ ${\bf P}(X=1)=\,$ ${\bf P}(X=0)=\,$______
${\bf P}(X=2)=\,$ ${\bf P}(X=1)=\,$______
${\bf P}(X=2)=\,$ ${\bf P}(X=1)=\,$______
${\bf P}(X=-2)=\,$ ${\bf P}(X=1)=\,$ ${\bf P}(X=0)=\,$______
${\bf P}(X=-2)=\,$ ${\bf P}(X=1)=\,$ ${\bf P}(X=0)=\,$______
已知a=[1 2 3; 4 5 6; 7 8 9],执行命令:a([3,1],:)=a([1,3],:),a将变为( )。 A: [4 5 6;4 5 6;4 5 6] B: [7 8 9;4 5 6;1 2 3] C: [2 2 2;5 5 5;8 8 8] D: [3 2 1;6 5 4;9 8 7]
已知a=[1 2 3; 4 5 6; 7 8 9],执行命令:a([3,1],:)=a([1,3],:),a将变为( )。 A: [4 5 6;4 5 6;4 5 6] B: [7 8 9;4 5 6;1 2 3] C: [2 2 2;5 5 5;8 8 8] D: [3 2 1;6 5 4;9 8 7]
${\bf P}(X=4)=\,$ ${\bf P}(X=3)=\,$ ${\bf P}(X=2)=\,$ ${\bf P}(X=1)=\,$______
${\bf P}(X=4)=\,$ ${\bf P}(X=3)=\,$ ${\bf P}(X=2)=\,$ ${\bf P}(X=1)=\,$______
设\( {\bf{A}} \) 为三阶矩阵,\( { { \bf{A}}^*} \)是\( {\bf{A}} \)的伴随矩阵,且\( \left| {\bf{A}} \right| = 1 \),则\( \left| {2 { { \bf{A}}^{ - 1}} + 3 { { \bf{A}}^*}} \right| = \)______
设\( {\bf{A}} \) 为三阶矩阵,\( { { \bf{A}}^*} \)是\( {\bf{A}} \)的伴随矩阵,且\( \left| {\bf{A}} \right| = 1 \),则\( \left| {2 { { \bf{A}}^{ - 1}} + 3 { { \bf{A}}^*}} \right| = \)______
选择对应的三视图。[img=100x101]1803bf2e7e3e5dd.png[/img][img=700x401]1803bf2e8a91dd2.png[/img] A: (1) B: (2) C: (3) D: (4) E: (5) F: (6)
选择对应的三视图。[img=100x101]1803bf2e7e3e5dd.png[/img][img=700x401]1803bf2e8a91dd2.png[/img] A: (1) B: (2) C: (3) D: (4) E: (5) F: (6)
存在多维数组arr,arr =np.array([[1 2 3] [4 5 6] [7 8 9]])数组arr.T的输出为 A: array([[1, 4, 7], [2, 5, 8], [3, 6, 9]]) B: array([[1, 2, 3], [4, 5, 8], [7, 6, 9]]) C: array([[1, 4, 7], [2, 5, 6], [3, 8, 9]]) D: array([[9, 4, 7], [2, 5, 8], [3, 6, 1]])
存在多维数组arr,arr =np.array([[1 2 3] [4 5 6] [7 8 9]])数组arr.T的输出为 A: array([[1, 4, 7], [2, 5, 8], [3, 6, 9]]) B: array([[1, 2, 3], [4, 5, 8], [7, 6, 9]]) C: array([[1, 4, 7], [2, 5, 6], [3, 8, 9]]) D: array([[9, 4, 7], [2, 5, 8], [3, 6, 1]])
配合物 [ Pt (en)2 ] Cl ,配位数为( ) A: 2 B: 4 C: 6 D: 8 E: 9
配合物 [ Pt (en)2 ] Cl ,配位数为( ) A: 2 B: 4 C: 6 D: 8 E: 9
若有a = [2*x for x in range(4)],语句print(a)输出为 A: [2, 4, 8,16] B: [2, 4, 6, 8] C: [1, 2, 4, 8] D: [0, 2, 4, 6]
若有a = [2*x for x in range(4)],语句print(a)输出为 A: [2, 4, 8,16] B: [2, 4, 6, 8] C: [1, 2, 4, 8] D: [0, 2, 4, 6]