ABSTRACT
The number of possible cases is too great for us to be exhaustive, so we shall restrict ourselves to two which most clearly exhibit the sorts of phenomena which can arise. These are:
ϕ equal wave number/frequency and amplitude, differing phase, k1 = k2 = k, ω1 = ω2 = ω, A1 = A2 = A, while ϕ2 = ϕ1 + ϕ, and
ν , λ equal amplitude and phase, differing wave number/frequency, A1 = A2 = A, ϕ2 = ϕ1 = 0, while k1 6= k2 and ω1 6= ω2.
