- #1

PhysicsandMathlove

While I was in there I noticed he was incorrectly teaching the mathematics of surface integrals.

For example:

The professor stated that for a sphere centered at the origin, the area element dA was found as follows.

Since, for a sphere the surface area is A=4πr

^{2}it follows that dA=8πrdr. He gave similar arguments for cylindrical and other symmetries. So far, this has not affected the examples since most of them have symmetries which have the E field constant on the surfaces in question so that it reduces to just an integral over dA.

Normally, I don't mind correcting a professor if there is a simple error, but this shows there is a severe lack of fundamental understanding of the math required. Never was there mention of parameterizing the surface and obtaining the

*correct*area element by means of the vector product of partial derivatives. Even worse, the fact that he is integrating

*over r*on the surface of the sphere is bothersome. I feel awkward correcting him because this is such a fundamental requirement for surface integrals. I don't know what I should do.