1.
If A=(15252515)A = \begin{pmatrix} \tfrac{1}{\sqrt{5}} & \tfrac{2}{\sqrt{5}} \\ -\tfrac{2}{\sqrt{5}} & \tfrac{1}{\sqrt{5}} \end{pmatrix}, B=(10i1)B = \begin{pmatrix} 1 & 0 \\ i & 1 \end{pmatrix}, i=1i = \sqrt{-1}, and Q=ATBAQ = A^T B A, then the inverse of the matrix AQ2021ATA Q^{2021} A^T is equal to: