On the adjoint matrix |(1 2) (3 4)| A11=(-1)^2*4=4 A12=(-1)^3*3=-3 A21=(-1)^3*2=-2 A22=(-1)^4*1=1 Why is its adjoint matrix not | (4 - 3) (- 21) |, but | (4 - 2) (- 31) |?

On the adjoint matrix |(1 2) (3 4)| A11=(-1)^2*4=4 A12=(-1)^3*3=-3 A21=(-1)^3*2=-2 A22=(-1)^4*1=1 Why is its adjoint matrix not | (4 - 3) (- 21) |, but | (4 - 2) (- 31) |?


The adjoint matrix of matrix A is the "transpose matrix" of the algebraic co submatrix of a (where a is a matrix of second order or greater)
Note: transpose matrix



What is the adjoint matrix?


The adjoint matrix of a is formed by transposing the algebraic cofactors of the elements of a matrix into a new matrix
The algebraic cofactor of an element is the determinant of the matrix formed by removing the row and column elements of an element in the matrix, and then multiplied by the power of - 1 (number of rows + number of columns)