% #33, p. 326 A=[-6 4 0 9; -3 0 1 6; -1 -2 1 0; -4 4 0 7] % the eigenvalues of A ev=eig(A) rref(A-ev(1)*eye(4)) rref(A-ev(2)*eye(4)) rref(A-ev(3)*eye(4)) % here are bases for the null spaces: null(A-ev(1)*eye(4)) null(A-ev(2)*eye(4)) null(A-ev(3)*eye(4)) % You can get the eigenvectors all at once, as follows: [V,d]=eig(A) % Now we'll check to see if they behave as we suspect they should: (A-ev(3)*eye(4))*null(A-ev(3)*eye(4)) (A-ev(3)*eye(4))*V