Oscillation and wandering of solutions to a second order differential equation

The Lyapunov's oscillation and wandering characteristics of solutions to a second order linear equation are defined, namely, the mean frequency of a solution, of its derivative or their various linear combinations, the mean angular velocity of the vector composed of a solution and its derivative, also wandering indices derived from that velocity. Nearly all of the values introduced for any equation are proved to be the same: for the autonomic equation – just all (moreover they coincide with the modules of the imaginary parts of the roots of the characteristic polynomial), but even for the periodic one – generally speaking, not all.