“…One of the sets of differential equations that find applications in real life is the oscillatory problems. In particular, the third-order differential equations arise in many important numbers of physical problems, such as the deflection of a curved beam having a constant or a varying cross-section, three-layer beam, the motion of the rocket, thin-film flow, electromagnetic waves, or gravity-driven flows [1,4,11,16,23,33,36]. Therefore, third-order differential equations have attracted considerable attention over the last three decades, and so many theoretical and numerical studies dealing with such equations have appeared in the literature (see [3,38] and references therein).…”