Ufyukyu

up vote 0 down vote favorite Find a matrix $B$ such that $B^{5}$ is equal to $begin{bmatrix} 20 & 12\ 19 & 13\ end{bmatrix}$ . I have tried this using the $2times2$ matrix $begin{bmatrix} a & b\ c & d\ end{bmatrix}$ and multiplying it by itself $5$ times but that has left me with polynomials of very high degrees. Any hints on how to start this? matrices share | cite | improve this question edited yesterday Tianlalu 2,594 6 32 asked yesterday Robbie Meaney ...