“…Calculus of variation is a technique used to solve the problems appearing in diverse fields, eg., dynamics of rigid body, optimization of orbit [10], flight design [9,13], etc. Optimality conditions and duality results for various classes of nonconvex variational problems have been of much interest in recent years, and several contributions have been made to its development (see, for example, [1,6,12,14,15,20]).…”