n . Vu = 0, on I'wall n . Vu + iku = 0, on Tout n . Vu + iku = 2ik, on I'in Here, the domain boundary I' = On is decomposed into the three parts I = Iwall UPout U Tin. For a computed solution u, we will also calculate its intensity at the output boundaries: H(u) lu|2 ds, (5) out where | . | is the complex absolute value. (a) Derive a Galerkin finite element formulation for (1)-(4), for an appropriate space V, of continuous piece-wise linear functions