Q. 193.7( 3 Votes )

# Matrices A and B are inverse of each other only when

A. AB=BA

B. AB=BA=0

C. AB=0, BA=I

D. AB=BA=I

Answer :

A = B^{-1}

B=A^{-1}

We know that

AA^{-1}= I

(Given B=A^{-1})

AB= I ------ 1

We know that

BB^{-1}= I

(Given A=B^{-1})

BA= I ------ 2

From 1 and 2

AB= BA = I

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