(i) For the determinant $\begin{vmatrix} 1 & 0 & 0 \\ 0 & 1 & 0 \\ 0 & 0 & 1 \end{vmatrix}$: Minors:

$$M_{11} = 1, M_{12} = 0, M_{13} = 0$$ $$M_{21} = 0, M_{22} = 1, M_{23} = 0$$ $$M_{31} = 0, M_{32} = 0, M_{33} = 1$$

Cofactors: Since $A_{ij} = (-1)^{i+j} M_{ij}$, the cofactors are:

$$A_{11} = 1, A_{12} = 0, A_{13} = 0$$ $$A_{21} = 0, A_{22} = 1, A_{23} = 0$$ $$A_{31} = 0, A_{32} = 0, A_{33} = 1$$

(ii) For the determinant $\begin{vmatrix} 1 & 0 & 4 \\ 3 & 5 & -1 \\ 0 & 1 & 2 \end{vmatrix}$: Minors: $M_{11} = \begin{vmatrix} 5 & -1 \\ 1 & 2 \end{vmatrix} = 11$, $M_{12} = \begin{vmatrix} 3 & -1 \\ 0 & 2 \end{vmatrix} = 6$, $M_{13} = \begin{vmatrix} 3 & 5 \\ 0 & 1 \end{vmatrix} = 3$ $M_{21} = \begin{vmatrix} 0 & 4 \\ 1 & 2 \end{vmatrix} = -4$, $M_{22} = \begin{vmatrix} 1 & 4 \\ 0 & 2 \end{vmatrix} = 2$, $M_{23} = \begin{vmatrix} 1 & 0 \\ 0 & 1 \end{vmatrix} = 1$ $M_{31} = \begin{vmatrix} 0 & 4 \\ 5 & -1 \end{vmatrix} = -20$, $M_{32} = \begin{vmatrix} 1 & 4 \\ 3 & -1 \end{vmatrix} = -13$, $M_{33} = \begin{vmatrix} 1 & 0 \\ 3 & 5 \end{vmatrix} = 5$

Cofactors:

$$A_{11} = 11, A_{12} = -6, A_{13} = 3$$ $$A_{21} = 4, A_{22} = 2, A_{23} = -1$$ $$A_{31} = -20, A_{32} = 13, A_{33} = 5$$