Lagrange multiplier condition

At a constrained extremum of f subject to g = 0, the gradient of f is parallel to the gradient of g, with the scalar λ as the proportionality factor. It is used to find maxima and minima of a function under an equality constraint.

\nabla f(x,y) = \lambda \nabla g(x,y)

What the symbols mean

objective function being optimized
constraint function, with the feasible set given by g(x,y)=0
Lagrange multiplier, a scalar
gradient operator with respect to x and y

About this formula

  • FieldMathematics
  • TopicOptimization
  • LevelUniversity
  • Also calledLagrange multipliers, method of Lagrange multipliers, constrained optimization Lagrange, Lagrangian stationary condition, undetermined multiplier, optimization with constraint
  • SourceWikidata Q598870

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