If A = \left( {\matrix{
{{1 \over {\sqrt 5 }}} & {{2 \over {\sqrt 5 }}} \cr
{{{ - 2} \over {\sqrt 5 }}} & {{1 \over {\sqrt 5 }}} \cr
} } \right), B = \left( {\matrix{
1 & 0 \cr
i & 1 \cr
} } \right), , and Q = A^TBA, then the inverse of the matrix A Q²⁰²¹ A^T is equal to :