Determinant van $$$\left[\begin{array}{cc}5 - \lambda & -4\\-4 & 5 - \lambda\end{array}\right]$$$
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Uw invoer
Bereken $$$\left|\begin{array}{cc}5 - \lambda & -4\\-4 & 5 - \lambda\end{array}\right|$$$.
Oplossing
De determinant van een 2x2-matrix is $$$\left|\begin{array}{cc}a & b\\c & d\end{array}\right| = a d - b c$$$.
$$$\left|\begin{array}{cc}5 - \lambda & -4\\-4 & 5 - \lambda\end{array}\right| = \left(5 - \lambda\right)\cdot \left(5 - \lambda\right) - \left(-4\right)\cdot \left(-4\right) = \lambda^{2} - 10 \lambda + 9$$$
Antwoord
$$$\left|\begin{array}{cc}5 - \lambda & -4\\-4 & 5 - \lambda\end{array}\right| = \left(\lambda - 9\right) \left(\lambda - 1\right)$$$A