提出了将二元函数极值化为一元函数极值的一种新方法;给出了二元函数极值存在的充分必要条件,改进了二元函数极值的判别法;并给出了判别式△=fxx(P0)fyy(P0)-fxx^2(P0)的几何意义.
The paper discusses a new method of transforming the binary function extreme value into the linear function extreme value by providing the sufficient and necessary conditions of the existence of the binary function extreme value, and hence improves the diseriminant method. It also gives the geometric meaning of the discriminant function △=fxx(P0)fyy(P0)-fxx^2(P0).