What is the inverse of A=(1001)A = \begin{pmatrix} 1 & 0 \\ 0 & 1 \end{pmatrix}A=(1001)?
(1001)\begin{pmatrix} 1 & 0 \\ 0 & 1 \end{pmatrix}(1001)
(0110)\begin{pmatrix} 0 & 1 \\ 1 & 0 \end{pmatrix}(0110)
(−100−1)\begin{pmatrix} -1 & 0 \\ 0 & -1 \end{pmatrix}(−100−1)
Does not exist