Question

After finding the minor \(M_{ij}\), what is the next step to find the cofactor \(C_{ij}\)?

Options

• Delete the \(i\)-th row and \(j\)-th column again.

• Set \(C_{ij}=M_{ij}\) in every case.

• Compute the sign factor \((-1)^{i+j}\).

• Expand along row \(i\).

Answer 1

The cofactor procedure first uses the already calculated minor \(M_{ij}\). It then computes the sign factor \((-1)^{i+j}\) before multiplication.