This paper presents the method of variational calculus in minimizing functionals containing second-order derivatives. The original theory of variational calculus was modified by the introduction of additional variables because of the second order derivatives involved in the functional. The extremum value of the functional was derived by solving the resulting differential equations from the solution Euler’s equation of the augmented functional.
Keywords: Augmented Functional, Auxiliary Equation, Euler’s equation., Lagrange Multiplier, Variational Calculus
