1. The problem statement, all variables and given/known data What phase difference between two otherwise identical traveling waves, moving in the same direction along a stretched string, will result in the combined wave having an amplitude 1.3 times that of the common amplitude of the two combining waves? Express your answer in (a) degrees, (b) radians, and (c) as a fraction of the wavelength. 2. Relevant equations Same frequency and amplitudes results in: y(x,t)=2ymcos(1/2Φ)sin(kx +/- wt +.5Φ) 3. The attempt at a solution Amplitude of resultant wave = 2ymcos(1/2Φ) 2ymcos(1/2Φ)=2.3ym solving for Φ : 2arccos(1.3/2)=Φ which is 1.7rad However, I'm not sure how to express this in terms of the wavelength.