information:classification
Lagrange multipliers

The Lagrange multiplier λ i {\displaystyle \lambda _{i}} is related to a constraint condition C i = 0 {\displaystyle C_{i}=0} and usually represents a force or a moment, which acts in “direction” of the constraint degree of freedom. The Lagrange multipliers do no "work" as compared to external forces that change the potential energy of a body.