Hi Gianluca;
Thank you so much for your response, because it certainly appears that your solution absolutely nailed the answer. I found it extremely interesting that you took both derivatives at once, within one derivative function, which created a single matrix containing both derivatives (x, y). Whereas, textbook examples show, taking two separate partial derivatives (one for x and another for y) and then combining them using a cross product before taking the norm. This method producing a different answer than obtained from using the SurfaceIntegrate[] function. Additionally, it seems that the method of combining two separate derivatives depends on whether the values are scalars or vectors (by adding scalars together or using the cross product to combine vectors) - is this correct?
Lastly, I noted that you used a function Minors[] which I am totally unfamiliar with. However, the function Minors[] did not seem to have any effect on the matrix, at least in my example, and therefore I was curious as to the intention of using it.
Again, thank you so much for your response, I certainly appreciate your time and insight, and I am still studying your solution to get a better understanding surface integrals.
Mitch Sandlin
