The discussion focuses on determining the amplitude of a resultant wave formed by the interference of two identical waves with a known phase difference. The approach involves writing the equations for both waves, A1 and A2, incorporating their respective phase shifts. By adding these wave equations, one can derive the amplitude of the resulting wave as a function of the original amplitude. Understanding the phase difference is crucial, as it directly influences the constructive or destructive interference observed in the resultant wave. This analysis is essential for solving problems related to wave interference in physics.