Determinants Matrices Question 61

Question: If adj $ B=A, $

$ | P |=| Q |=1, $ then adj $ ({Q^{-1}}B{P^{-1}}) $ is

Options:

A) $ PQ $

B) $ QAP $

C) $ PAQ $

D) $ P{A^{-1}}Q $

Show Answer

Answer:

Correct Answer: C

Solution:

  • [c] Given $ adjB=A,| P |=| Q |=1 $ Consider, adj $ ({Q^{-1}}B{P^{-1}}) $

$ =(adj{P^{-1}})(adjB)(adj{Q^{-1}}) $

$ ={{(adjP)}^{-1}}A.{{(adjQ)}^{-1}}={{({P^{-1}})}^{-1}}A{{({Q^{-1}})}^{-1}} $

$ =PAQ $ .