Q19 of 98 Page 314

Matrices A and B are inverse of each other only when

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

If A and B are square matrices of the same order then (A – B)² =?

If A and B are symmetric matrices of the same order then (AB – BA) is always

For square matrices A and B of the same order, we have adj(AB)=?

If A is a 3-rowed square matrix and │A│=4 then adj(adj A)=?