1. The problem statement, all variables and given/known data Two "waves", characterized by cosx and cos^2(x/2) interfere. Using phasors or complex numbers or trigonometry as necessary, aggregate "cosx + 2cos^2(x/2)" - i.e. rewrite as a single cosine. 2. Relevant equations I was told that there is an error in the way this questions was written and that cos is supposed to be cis cisθ = cosθ + isinθ 3. The attempt at a solution I don't know what to do. Am I supposed to replace all of the cosines in the original problem with cis?