测试mdnice¶

$D=\lambda\left|{\begin{array}{*{20}{c}}\lambda &{{\rm{-1}}}&{\rm{0}}\\{\rm{0}}&\lambda &{{\rm{-1}}}\\{\rm{3}}&{\rm{2}}&{\lambda+{\rm{1}}}\end{array}}\right|+{\rm{4}}\mathop{(-1)}\nolimits^{1+4}\left|{\begin{array}{*{20}{c}}{-1}&0&0\\\lambda &{-1}&0\\0&\lambda &{-1}\end{array}}\right|$ $=\lambda\left({\lambda\left|{\begin{array}{*{20}{c}}\lambda &{-1}\\2&{\lambda+1}\end{array}}\right|+3\left|{\begin{array}{*{20}{c}}{-1}&0\\\lambda &{-1}\end{array}}\right|}\right)+4$ = $\mathop \lambda \nolimits^{\rm{4}}+\mathop\lambda\nolimits^{\rm{3}}+\mathop{{\rm{2}}\lambda }\nolimits^{\rm{2}}+{\rm{3}}\lambda+{\rm{4}}$