1. The problem statement, all variables and given/known data Two Transverse Sinusoidal waves combine in a medium are described by the wave functions: y1 = 3sin∏(x + 0.600t) y2 = 3sin∏(x - 0.600t) what is y1 + y2? 2. Relevant equations the hint is that I am supposed to use: sin(α + β) = sin(α)cos(β) + cos(α)sin(β) 3. The attempt at a solution the answer in the back is: y = y1 + y2 = 6sin(∏x)cos(0.600∏t) I am not really sure how they got that. In fact,the notation of y1 and y2 confuse me because y1 says: y1=3sin∏(x + 0.600t) and I interpret this as 3 multiplied by sin∏ multiplied by (x+0.600t) but the problem is sin∏ = 0, so don't both equations just reduce to 0? y1 = 0 y2 = 0? Can someone clarify this for me?