Minors:Let A = [aij ] be an n n matrix.
1. For each i and j, we define the minor of aij , denoted Mij to be the
determinant of the matrix obtained by deleting the ith row and jth column
of A.
2. The cofactor of entry aij , denoted Cij is defined to be
Cij = (-1)^i+j Mij