Has anyone ever heard of the Jacovian or Jacobian law/theory

[land_of_ice]

Has anyone ever heard of the "Jacovian" or "Jacobian law/theory

the correct spelling for this word might be , "Jacobian" or "Jacovian", or something else, but it is a theory or a law or a rule? Does anyone know what it actually might be called, this is referring to a theory or rule or law that you might have to know for a doctorate in Electrical Engineering?

and that it takes about 2 hours just to explain the beginning of the theory.

 

[Studiot]

Well you might need to deal with systems of simultaneous equations arr anged in matrix format.

A Jacobian is a matrix of (partial) differential coefficiants roughly equivalent to dy/dx for a single variable, but acting on the whole set or matrix of equations.
They appear in some theory but also in numerical methods for solution of these equations.