关于条件极值充分条件的重新推导和证明

A New Derivation and Proof of the Sufficient Condition of Conditional Extreme Value

李文学用拉格朗日函数提出求条件极值的充分条件,但他的证明却是错误的.本文不用拉格朗日函数,而是直接通过消去一个变量将条件极值转化成无条件极值,重新推导出充分性条件.推导的过程也是条件极值充分条件的证明过程.

Wenxue Li put forward a sufficient condition of conditional extreme value with Lagrange function, but his proof is wrong. This text derives out the sufficient condition again no using Lagrange function, but direct eliminating a variable from the side condition to transform conditional extreme value into the unconditional extreme value. The derived course is also the proved course of a sufficient condition.