## What are cofactor elements?

A cofactor is a number that is obtained by eliminating the row and column of a particular element which is in the form of a square or rectangle. The cofactor is preceded by a negative or positive sign based on the element’s position.

### How do you calculate a cofactor?

To find the cofactor matrix of A , follow these steps:

- Cross out the i -th row and the j -th column of A .
- Compute the determinant of this submatrix.
- Determine the sign factor (-1)i+j .
- Multiply the (i, j) -minor of A by the sign factor.
- Repeat Steps 1-4 for all i,j = 1,…,n .

#### How do you calculate det?

To work out the determinant of a 3×3 matrix:

- Multiply a by the determinant of the 2×2 matrix that is not in a’s row or column.
- Likewise for b, and for c.
- Sum them up, but remember the minus in front of the b.

**What is a 4×4 matrix?**

Determinant of a 4×4 matrix is a unique number which is calculated using a particular formula. If a matrix order is n x n, then it is a square matrix. Hence, here 4×4 is a square matrix which has four rows and four columns. If A is square matrix then the determinant of matrix A is represented as |A|.

**What is cofactor of A?**

Definition of cofactor 1 : the signed minor of an element of a square matrix or of a determinant with the sign positive if the sum of the column number and row number of the element is even and with the sign negative if it is odd.

## How do you make a cofactor matrix?

How to Find the Co-factor Matrix?

- First, find the minor of each element of the matrix by excluding the row and column of that particular element, and then taking the remaining part of the matrix.
- Secondly, find the minor element value by taking the determinant of the remaining part of the matrix.
- .

### How do you find minors and cofactors?

Minor of an element in a matrix is defined as the determinant obtained by deleting the row and column in which that element lies. Cofactor of an element aij, is defined by Cij = (-1)i+j M, where M is minor of aij.