In the paper, we give the determination theorers and inferences about the positive and negative definite of quadratic form in some conditions base on literature[1], and thus extend the positive definite nature of quadratic form.%对二次型的正定性研究已取得丰硕成果，并为众多科学所应用．随着应用问题的研究，会遇到二次型在条件下的正定、负定问题，在文献[1]的基础上给出了二次型在某种条件下正定、负定性判别的新定理及推论，从而推广了二次型的正定性．
展开▼
