Let matrix B be the adjoint of a square matrix A, l be the identify matrix of same order as A. If k (≠ 0) is the determinate of the matrix A, then what is AB equal to? 

Let matrix B be the adjoint of a square matrix A, l be the identify matrix of same order as A. If k (≠ 0) is the determinate of the matrix A, then what is AB equal to?  Correct Answer kl

Concept:

Consider a matrix A and A is a square matrix.

A.adj (A) = adj (A).A = |A|I

Calculation:

Given:

B = adj (A)

I = Identity matrix

|A| = k

Now, AB = A.adj (A) = |A|I =KI

∴ Option 2 is correct.

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