[行列解析3.3.P25]

A^{-1} =
\begin{bmatrix}
-\tfrac{a_1}{a_0} & 1 & 0 & \cdots & 0 \\
-\tfrac{a_2}{a_0} & 0 & 1 & \cdots & 0 \\
\vdots & \vdots & \vdots & \ddots & \vdots \\
-\tfrac{a_{n-1}}{a_0} & 0 & 0 & \cdots & 1 \\
-\tfrac{1}{a_0} & 0 & 0 & \cdots & 0
\end{bmatrix}
\tag{3.3.18}

t^n + \tfrac{a_1}{a_0} t^{n-1} + \cdots + \tfrac{a_{n-1}}{a_0} t + \tfrac{1}{a_0}
= \tfrac{t^n}{a_0} \, p_A(t^{-1})
\tag{3.3.19}