1. \displaystyle A_{\boldsymbol{f}}=\begin{pmatrix}1&0\\0&0\end{pmatrix}.
2. >\displaystyle A_{\boldsymbol{e}}=TA_{\boldsymbol{f}}T^{-1}=\frac{1}{5}\begin{pmatrix}4&{-2}\\{-2}&1\end{pmatrix}.
