Given, $\{\dot{x}\} = [A]\{x\} + [B]\{u\}$, where $\{u\} = [K]\{x\}$. The matrices, A, B, and K are
$[A] = \begin{bmatrix} 0 & 1 \\ -1 & 0 \end{bmatrix}; [B] = \begin{bmatrix} 1 & 0 \\ 0 & 1 \end{bmatrix}; [K] = \begin{bmatrix} -k & 0 \\ 0 & -2k \end{bmatrix}$
Determine the value of "k" such that the system is critically damped ($\zeta = 1$)