Abstract:
A time-periodic system with one degree of freedom is investigated. The system is assumed to have
an equilibrium position, in the vicinity of which the Hamiltonian is represented as a convergent
series.This series does not contain members of the second degree, whereas the members to some
finite degree $\ell$ do not depend explicitly on time. The algorithm for constructing a canonical
transformation is proposed that simplifies the structure of the Hamiltonian in members to
degree $\ell$, inclusive. As an application, a special case is considered when the expansion of the
Hamiltonian begins with members of the third degree. For this case, sufficient conditions for
instability of the equilibrium are obtained depending on the forms of the fourth and fifth degrees.