<p>已知3阶实对称矩阵A的特征多项式<img src="https://learnfile.20230611.cn/learnAppQuestion/41/1a/411ae69fffae4cb13d0406aa032f67d1.jpg" style="width: 100%;height: auto;">则二次型<img src="https://learnfile.20230611.cn/learnAppQuestion/fe/21/fe212d7742d81016336fad2352529 - 线性代数（经管类）(04184)