Thread:E-team 2.532/@comment-43863981-20191024225306

whats the answer to this math problem have been stuck on it for 5 years send help and
 * {\displaystyle H_{2^{k}}={\begin{bmatrix}H_{2^{k-1}}&H_{2^{k-1}}\\H_{2^{k-1}}&-H_{2^{k-1}}\end{bmatrix}}=H_{2}\otimes H_{2^{k-1}},}

for {\displaystyle 2\leq k\in N}, where {\displaystyle \otimes } denotes 