数学最优问题中，拉格朗日乘数法（以数学家约瑟夫·路易斯·拉格朗日命名）是一种寻找变量受一个或多个条件所限制的多元函数的极值的方法。(In the mathematical optimization problem, the Lagrange multiplier method (named by the mathematician Joseph Luis Lagrange) is a method of finding the extremum of a multivariate function which is restricted by one or more conditions.)