3. Consider the block matrix A = D1 - B -C D2 where Di, D2, B, Care n x n matrices, and Di, De are non-singular. Let b e Ran and suppose we wish to find x 6 Ran such that Ax = b. (i) Write down the iteration matrices for the block Jacobi applied to this block matrix system. (ii) Show that the determinant of the matrix A satisfies det(A) = det(Dj) det(D2 - CD1-1 B). Let GJ denote the block Jacobi iteration matrix. Find an n * n matrix whose eigenvalues are related to the eigenvalues of G.J