【摘要】 从几何上3个曲面中任2个曲面的交线在三元函数取得极值的点处有公切线出发,得出了用目标函数、条件的偏导数组成的行列式表示的三元函数在2个条件下的极值的必要条件,并通过实例验证了结论的正确性。这是不同于Lagrange乘数法的一个必要条件。更多还原

【Abstract】 Starting from the fact that the intersecting curves of any two surfaces of three surfaces have common tangent at extreme point of tri-function,the necessary condition of extreme value of tri-function under two conditions by determinant of the partial derivatives of objective function was obtained.The correctness of the conclusions was verified by examples.This necessary condition is the one different from that of Lagrange multiplying number method.更多还原