(Courtesy: R.G. MacDonald, A. Yakovlev, and V. Pacheco-Peña, doi : 10.1117/1.APN.3.5.056007) Waveguide-based structures can solve partial differential equations by mimicking elements in standard ...
When integrating simple expressions, the constant of integration, the \(+ c\) term, may remain an unknown. The value of \(c\) can be worked out when additional information is given in the question, .