What is the characteristic polynomial of A=(01−10)A = \begin{pmatrix} 0 & 1 \\ -1 & 0 \end{pmatrix}A=(0−110)?
λ2−1\lambda^2 - 1λ2−1
λ2+1\lambda^2 + 1λ2+1
λ2+λ\lambda^2 + \lambdaλ2+λ
λ2−λ\lambda^2 - \lambdaλ2−λ