You may find this site helpful.
-Dan
Hello, I have a homework problem that I am not seeing quite well. Please help somebody.
1) Let A be a 4 by 4 matrix. If
adjoint A=
2 0 0 0
0 2 1 0
0 4 3 2
0 -2 -1 2
find A.
Answer from back of the book:
A=
1 0 0 0
0 4 -1 1
0 -6 2 -2
0 1 0 1
*I have no clue on how to go from Adjoint A to A.
I believe that the adjoint of A is equal to A. So find the adjoint of the adjoint.
You have to create a 4 x 4 matrix using the cofactor determinants. So
Then do the same for the other 15 cofactors determinants, then take the transpose of the resulting matrix. The website says that this is the adjoint, which I'll let you verify for yourself.
-Dan