Can anyone explain to me what is the cofactor matrix? I have trouble finding on the net the intuition behind it. Likewise what is the meaning of the adjugate matrix?
This is a lesson in linear algebra. Probably it would be good to consult your linear algebra book about this for a thorough understanding.
A cofactor matrix is a matrix whose entries are the cofactors of some other matrix. While the adjugate matrix is simply the transpose of the cofactor matrix.
Hopefully you learned how to take co-factors when finding determinants. The cofactor of some entry ##A_{ij}## in a matrix ##\bf{A}## is the determinant of the resulting matrix when you delete the ith row and j'th column of the matrix ##\bf{A}## and then accounting for an alternating sign, a factor of ##(-1)^{i+j}##.