1. The problem statement, all variables and given/known data how do you add two waves with the same frequency but different phases? E1 = 7*sin(omega*t + 70degrees) E2 = 13*sin*(omega*t + 65degrees) 2. Relevant equations Er = E1 + E2 3. The attempt at a solution I know how to add waves that only have one phase, i.e. E1 = E01*sin(omega*t) E2 = E02*sin(omega*t + phase difference) Can I subtract 65-70 degrees to make it E1= E01*sin(omega*t) E2 = E02*sin(omega*t - 5degrees) ?