Cofactor matrix of a 4x4 matrix

Last updated: Jan. 2nd, 2019
  Find the cofactor matrix of
cofactor matrix 4x4

  Proof

  Let $M_{ij}$ be a submatrix given by removing $i$-th row and $j$-th column from $A$,
Each element of the cofactor matrix $\tilde{A}$ of $A$ is defined as
cofactor matrix definition
(Note that the subscript order of $M$ is different from that of $\tilde{A}$). The determinant of $M_{ij}$ is respectively
(See 3x3 determinant). Therefore, each element of $\tilde{A}$ is
Calculator
  Enter a 4x4 matrix and press "Execute" button. Then the cofactor matrix is displayed.
Matrix $A$
1 2 3 4
1
2
3
4

Cofactor matrix $\tilde{A}$
1 2 3 4
1
2
3
4