When coherent waves are added, an interference pattern of maxima and minima of illumination arises, stable in time, and at the maxima the energy is greater than the sum of the energies from both terms of the waves, and at the minima the energy is zero. With interference, a redistribution of energy occurs between the interference maxima and minima, but the average value of the energy at all points of the interference pattern is equal to the sum of the energies brought by both waves.
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.