\begin{equation*}
U_A^{D_A} = \left[\begin{array}{c c}
1 & 2\\
0 & 1
\end{array}\right]-
\left[\begin{array}{ c c }
1.5 & .5-\varepsilon \\
0 & -.5
\end{array}\right] = 
\left[\begin{array}{ c c }
-.5 & 1.5+\varepsilon \\
0 & 1.5
\end{array}\right]
\end{equation*}
