Find the characteristic polynomial of A=[100021003]A = \begin{bmatrix} 1 & 0 & 0 \\ 0 & 2 & 1 \\ 0 & 0 & 3 \end{bmatrix}A=100020013
−(λ−1)(λ−2)(λ−3)-(\lambda - 1)(\lambda - 2)(\lambda - 3)−(λ−1)(λ−2)(λ−3)
(λ−1)(λ−2)2(λ−3)(\lambda - 1)(\lambda - 2)^2(\lambda - 3)(λ−1)(λ−2)2(λ−3)
λ3−6λ2+11λ−6\lambda^3 - 6\lambda^2 + 11\lambda - 6λ3−6λ2+11λ−6
(1−λ)(2−λ)(3−λ)(1 - \lambda)(2 - \lambda)(3 - \lambda)(1−λ)(2−λ)(3−λ)