Science and The Industrial Design Engine
A rod is to be laid across an engine in order to operate a fuel system unit. You do not want the rod to vibrate with resonant frequency when the engine is in cruise mode. The industrial designer is then given a formulae, rather long, in order to establish what rod diameters must be avoided.
The industrial designer uses the formulae in the same way that a mechanic would lift up a spanner, and that is it.
The formulae most useful but absolutely nothing to do with the design of the rod.