最小多项式(minimalpolynomial)是代数数论的基本概念之一。由Cayley-Hamilton定理,A的特征多项式是A的零化多项式,而在A的零化多项式中,次数最低的首一多项式称为A的最小多项式。
最小多项式的求解方法
方法:
1、先将A的特征多项式
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在P中作标准分解,找到A的全部特征值
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的因式按次数从低到高的顺序进行检测,第一个能零化A的多项式就是最小多项式。
例:
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的最小多项式。
解:A的特征多项式为:
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又
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故A的最小多项式为
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扩展资料
特征多项式的解法
1、把|λE-A|的各行(或各列)加起来,若相等,则把相等的部分提出来(一次因式)后,剩下的部分是二次多项式,肯定可以分解因式。
2、把|λE-A|的某一行(或某一列)中不含λ的两个元素之一化为零,往往会出现公因子,提出来,剩下的又是一二次多项式。
3、试根法分解因式。
根据特征矩阵xE-A的标准形,其中次数最高的不变因子就是最小多项式
根据Jordan标准形
求次数最小的首项系数为1的零化多项式
根据有理标准型
初等因子等