5.1 Functionals and stationary points
 5.2 Stationary points
 5.3 Special cases with examples: first integrals
  5.3.1 Functional of first derivative only
  5.3.2 No explicit dependence on x
 5.4 Generalisations
  5.4.1 Variable end points
  5.4.2 One endpoint free
  5.4.3 More than one function: Hamilton’s principle
  5.4.4 More dimensions: field equations
  5.4.5 Higher derivatives
 5.5 Constrained variational problems
  5.5.1 Lagrange’s undetermined multipliers
  5.5.2 Generalisation to functionals
  5.5.3 Eigenvalue problems
  5.5.4 The Rayleigh-Ritz method