cofactor {RConics}

(i,j)-cofactor and (i,j)-minor of a matrix

Description

Compute the (i,j)-cofactor, respectively the (i,j)-minor of the matrix A. The (i,j)-cofactor is obtained by multiplying the (i,j)-minor by (-1)^{i+j}. The (i,j)-minor of A, is the determinant of the (n - 1) \times (n - 1) matrix that results by deleting the i-th row and the j-th column of A.

Usage

cofactor(A, i, j)

minor(A, i, j)

Arguments

A

a square matrix.

i

the i-th row.

j

the j-th column.

Value

The (i,j)-minor/cofactor of the matrix A (single value).

See Also

adjoint

Examples

A <- matrix(c(1,4,5,3,7,2,2,8,3),nrow=3,ncol=3)
A
minor(A,2,3)
cofactor(A,2,3)