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[单选题]
设A与B均为n阶方阵,则下列结论成立的是()。
A.det(AB)=0,则4=O,或B=O
B.det(AB)=0,则detA=0,或detB=0
C.AB=O,则4=0,或B=O
D.AB≠O,则detA≠0,或detB≠0
查看答案
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A.det(AB)=0,则4=O,或B=O
B.det(AB)=0,则detA=0,或detB=0
C.AB=O,则4=0,或B=O
D.AB≠O,则detA≠0,或detB≠0
设A,B皆为n阶方阵,证明:
r(AB)≥r(A)+r(B)-n,
并问:若上述结论是否成立?
设A,B均为n阶方阵,证明下列命题等价:
(1)AB=BA (2)(A±B)2=A2±2AB+B2(3)(A-B)(A-B)=A2-B2
(A)A=C-1B-1(B)BAC=E (C)BCA=E (D)CAB=E
A.|A+B|=|A|+|B|
B.|(A+B)-1|=|A|-1+|B|-1
C.|kAB|=kA|·|B|
D.l(AB)k|=|A|k·|B|k