I'm getting so confused about this question, any help would be great. :) 1. The problem statement, all variables and given/known data Two infinite waves Ψ1, Ψ2 have the same wavelength and polarisation and have amplitudes of E1 = 3 and E2 = 7 units. They are added together with a phase difference of 125 degrees. 1) What will be the relative intensity of the resultant wave? Assume initial phase of 0 degrees for Ψ1. 2) In the same conditions, what will be the phase of the resultant wave (in degrees)? 2. Relevant equations N/A 3. The attempt at a solution So far I've got Ψ1=3sin(kx-ωt) and Ψ2=7sin(kx-ωt+2.182) And I know that I is proportional to A squared. Now I'm pretty stuck!