1. The problem statement, all variables and given/known data Please kindly help me. Actually I dont quite understand what the meaning of harmonic wave is and the mathematics that expresses it. h(x,y;t) = h sin(wt-kx+δ) h represents the position of the particle in a particular time? Or the wave motion? What is the physical meaning of w, k? What are they describing? Why the function is written as h sin(wt-kx+d)? Can you explain that? My mathematic is not very good, to be honest. 1) What is the distance between two maxima/minima in an interference pattern of two waves u1 and u2 described by u1(x) = cos(k1 x); u2(x) = cos(k2 x) What happens when k1=k2? 2) "The so-called nami-water is good to our body!" Is the statement scientific (falsifiable), and why? 2. Relevant equations 3. The attempt at a solution The distance between two maxima/minima in an interference pattern = the interfered wave's wavelength?