Solution (source code)

= Solution

The grazing-gap signal is the chord \b[from $F(0)=0$ to $F(1.768)$], approximately $(0.3245,0.4818)$ in the (C,S) plane. Its squared length determines received power after applying the same propagation normalization used for the open field. Reversing which gap edge grazes the ray reflects both limits and leaves the power unchanged.