If A = and B is a square matrix of order 2 such that AB=I then B=?
B=I
B = A-1 I ---------1
A-1= adj A --------- 2
= 3 x 2 – (-4) x (-1)
2
C11 = 2 C12 = 1
C21= 4 C22 = 3
Cofactor matrix A =
Adj A =’
=
Putting in 2
A-1=
=
Putting in 1
B = A-1 I
= A-1
=