利用二次型判别多元函数的极值

Extreme Test for Functions of Several Variables by use of Quadratic Forms

利用二次型的正定性和负定性讨论多元函数的极值判别法并应用到二元函数上．

The article discusses the extreme test for functions of several vedables by use of positive and neqative definite quadratic forms, and we study it's applications to the functions of two variables.