3) [10 points] Objective: Use the superposition principle to compute the more complex behavior of the sum of 2 waves. This is a basic example of how waves of any shape can be made by adding harmonic waves. Consider two monochromatic waves of the same speed, equal amplitude and no phase delay in 1D. Both waves are propagating in the +z direction, but have different frequencies different frequencies w and @, . Show that their sum can be expressed as the product of two monochromatic waves with different frequencies but the same speed. [Hint: Write the waves in terms of the mean and difference of w, and w, ]