Self-oscillations are not damped by adjusting the energy supply from the source when an alternating voltage source is included in the circuit. Free oscillations occur when the system is removed from the equilibrium position and damp, since part of the energy imparted to the system inevitably gradually turns into heat released at the active resistance.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.