Remarks
(i)
For easier calculations, we shall expand the determinant along that row or column
which contains maximum number of zeros (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