如果第三问只有第三问解题步骤
第一步:利用|λE-A|=0,求出A的特征值λ1,λ2,λ3
第二步:①求出λ1对应的基础解系ξ1,利用(λ1E-A)x=0,
②求出λ1对应的基础解系ξ2,利用(λ2E-A)x=0
③求出λ1对应的基础解系ξ3,利用(λ3E-A)x=0
第二步中若λ1=λ2,基础解系ξ1,基础解系ξ2,可能不正交(相乘不等于0),要进行正交化
若λ1≠λ2≠λ3,基础解系ξ1,ξ2,ξ3必定相互正交,无需正交化
第三步:单位化ξ1,ξ2,ξ3(若ξ1,ξ2非正交一定要先正交化)
ξ1,ξ2,ξ3经正交化单位化分别变为p1,p2,p3
第四步:(1)写出P(p1,p2,p3) 列向量pi就是P的第i列
(2)新的二次形f=λ1y1^2+λ2y2^2+λ3y3^2
特别注意:λi一定要与pi对应
追问漏了变换前的二次型f的表示式诶
我知道了
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