Welke matrix is NIET idempotent ?
[ Een vierkante matrix A is idempotent als A² = A ]
ABCDE
\(\small\begin{bmatrix}1 & 0 \\0 & 1 \end{bmatrix}\) \(\small\begin{bmatrix}0 & 1 \\1 & 0 \end{bmatrix}\) \(\small\begin{bmatrix}0 & 0 \\0 & 0 \end{bmatrix}\) \(\small\begin{bmatrix}1 & 0 \\0 & 0 \end{bmatrix}\) \(\small\begin{bmatrix}2 & 1 \\-2 & -1 \end{bmatrix}\)
A    B    C    D    E

[ 5-7894 - op net sinds 19.6.15-(E)-20.10.2026 ]

Translation in   E N G L I S H

Which matrix is NOT idempotent ?
ABCDE
\(\small\begin{bmatrix}1 & 0 \\0 & 1 \end{bmatrix}\) \(\small\begin{bmatrix}0 & 1 \\1 & 0 \end{bmatrix}\) \(\small\begin{bmatrix}0 & 0 \\0 & 0 \end{bmatrix}\) \(\small\begin{bmatrix}1 & 0 \\0 & 0 \end{bmatrix}\) \(\small\begin{bmatrix}2 & 1 \\-2 & -1 \end{bmatrix}\)

Oplossing - Solution

\(De\;tweede\;want\\\\\begin{bmatrix}0&1\\1 &0\end{bmatrix}\cdot \begin{bmatrix}0&1\\1 &0\end{bmatrix}=\begin{bmatrix}1&...\\... &...\end{bmatrix}\)
gricha