Why don't you do your best?
"If people do not believe that mathematics is simple, it is only because they do not realize how complicated life is complicate." – John von Neumann
4 Why the heat flux vector at a point must be perpendicular to the temperature isothermal surface? Is it a definition or a deduction? jun 4 '13
1 How could flux can be a vector and a scalar? jun 6 '13