If A=PDP−1A = P D P^{-1}A=PDP−1, which matrix is equal to AkA^kAk?
PDkPP D^k PPDkP
PDkP−1P D^k P^{-1}PDkP−1
PkDkP−kP^k D^k P^{-k}PkDkP−k
DkD^kDk