Some results on the numerical integration of the equation \(\ddot \theta + k \dot \theta + (1 + 2q \cos \Omega t) \sin \theta = 0\) are presented. The damping \(k\) has been chosen as \(k = 0.2\) for a reasonable approximation to the effect of friction. The parameters \(q\) and \(\Omega\) belong to the rectangle \(0.8 \leq \Omega \leq 2.4\); \(0 \leq q \leq 1.6\); containing the principal resonant frequencies \(\Omega = 1,2\). It has been found out that there are three general categories of motions: a) no rotation, b) rotation changing its direction with time, c) rotation in a single direction. Special attention is paid to oscillatory responses. Results are exposed via numerous diagrams.
For the entire collection see [Zbl 0802.00023].