1. The problem statement, all variables and given/known data Hey all, I am working through a derivation that my professor gave me to do and I am having trouble understanding one of the formulas that he gave me, namely: "EM waves can be described as: E(x, t) = Eosin(2πx/λ)*sin(2πc/λ)" The the Eo*sin(2πx/λ) term makes sense to me. I am wondering why there is a second sin term (the sin(2πc/λ)) term in the equation. I understand that c/λ = f, but in that case I still don't really understand why this term is in here. Is there a source that derives this equation anywhere? I am having trouble finding a way to understand this equation.