(ii)
While expanding, instead of multiplying by (–1)i + j, we can multiply by +1 or –1
according as (i + j) is even or odd (iii)
Let A = 2
2
4
0






 and B = 
1
1
2
0





 Then, it is easy to verify that A = 2B Also
|A| = 0 – 8 = – 8 and |B| = 0 – 2 = – 2