摘要
归纳总结了不定乘子的由来、意义和作用，提出在非完整力学系统中，不定乘子的引入是解决问题的一把钥匙。
This paper sums up the origin, significance and action of undetermined multipiers, puts forward the view that the introduction of undetermined multipiers to nonholonomic dynamical system is the key to deal with the problem.
关键词
不定乘子
非完整约束
广义约束力
Undetermined multipier
Nonholonomic constraint
Generalized forces of constraints
Lagrange's equation
Routh's equation
APPell's equation
