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Question: Answered & Verified by Expert
If A is an 3×3 non- singular matrix, such that AA'=A'A and B=A-1A', then BB' equals to
MathematicsMatricesBITSATBITSAT 2019
Options:
  • A B-1'
  • B I+B
  • C I
  • D B-1
Solution:
1732 Upvotes Verified Answer
The correct answer is: I

Given,

AA'=A'A

and B=A-1A'

BB'=A-1A'A-1A''

=A-1A'A''A-1'

=A-1A'AA'-1

 A''=A,A-1'=A'-1

=A-1A'AA'-1

=A-1AA'A'-1

=A-1AA-1A'

=I·I=I

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