Elementary Integrability of Polynomial Rayleigh–Duffing Systems
摘要
By investigating the invariant algebraic curves whose cofactors are the divergence of the system multiplied by an integer, we obtain the necessary and sufficient conditions for polynomial Rayleigh–Duffing systems (except Liénard systems) to have elementary first integrals. It is shown that rewriting the polynomial equation of the invariant algebraic curve as a Weierstrass polynomial equation is useful.