If a is square matrix of order 3 and Aij and cofactor of element Aij t...
Introduction:
In linear algebra, the cofactor of an element in a square matrix is a key concept. It is directly related to the determinant of the matrix and can be used to find the inverse of the matrix. In this case, we have a square matrix of order 3, denoted as A, and we need to find the value of the cofactor Aij.
Explanation:
To understand the concept of cofactors, we first need to understand the concept of minors. The minor of an element Aij in a matrix A is the determinant of the submatrix obtained by deleting the ith row and jth column of A. Let's denote the minor of Aij as Mij.
Formula for Cofactor:
The cofactor of an element Aij is given by the formula:
Cij = (-1)^(i + j) * Mij
Steps to Find the Cofactor:
1. Find the minor Mij by deleting the ith row and jth column of the matrix A.
2. Calculate the cofactor Cij using the formula mentioned above.
Application to Matrix A:
Since we have a square matrix of order 3, we need to find the cofactor Aij for each element Aij in the matrix A. Let's denote the elements of the matrix A as A11, A12, A13, A21, A22, A23, A31, A32, and A33.
1. Cofactor of A11: Calculate the minor M11 by deleting the 1st row and 1st column of matrix A. Then, use the formula to find the cofactor C11.
2. Cofactor of A12: Calculate the minor M12 by deleting the 1st row and 2nd column of matrix A. Then, use the formula to find the cofactor C12.
3. Cofactor of A13: Calculate the minor M13 by deleting the 1st row and 3rd column of matrix A. Then, use the formula to find the cofactor C13.
4. Cofactor of A21: Calculate the minor M21 by deleting the 2nd row and 1st column of matrix A. Then, use the formula to find the cofactor C21.
5. Cofactor of A22: Calculate the minor M22 by deleting the 2nd row and 2nd column of matrix A. Then, use the formula to find the cofactor C22.
6. Cofactor of A23: Calculate the minor M23 by deleting the 2nd row and 3rd column of matrix A. Then, use the formula to find the cofactor C23.
7. Cofactor of A31: Calculate the minor M31 by deleting the 3rd row and 1st column of matrix A. Then, use the formula to find the cofactor C31.
8. Cofactor of A32: Calculate the minor M32 by deleting the 3rd row and 2nd column of matrix A. Then, use the formula to find the cofactor C32.
9. Cofactor of A33: Calculate the minor M33 by deleting the 3rd row and 3rd column of matrix A. Then, use the formula to find the cofactor C33.
Conclusion