1. The problem statement, all variables and given/known data The figure shows a snapshot of three waves traveling along a string, where x,t are in SI units. The phases for the waves are given by... the picture and problem is in this link http://img339.imageshack.us/img339/2407/phys1prob.th.png [Broken] 2. Relevant equations (kx-wt) lambda=2pi/k 3. The attempt at a solution Basiclly I think I can solve the rest if i understand this problem. The wavelength= 2pi ? but when i solve for k... k=2pi/lambda, k is one. the answer should give me that k is 2, and the only way i can get that is if the wavelength is pi. Can anyone please help me to understand this?