Let A {\textstyle A} be a 2 × 2 {\textstyle 2\times 2} matrix with eigenvalues 1 + i {\textstyle 1+i} , 1 − i {\textstyle 1-i} . Find A 4 {\textstyle A^{4}} . (Hint: how does A 4 {\textstyle A^{4}} transform the eigenvectors?)