This document, located at http://new.math.uiuc.edu/math280, was last edited 8feb98 gfrancis@uiuc.edu

The first page this week has an exhaustingly detailed solution to the quiz last Friday. While the average score was somewhat better than last week, this was an unusually easy quiz, and more people should have gotten a 10.

Notes for Shey, Chapter 2. Gauss' Formula and the Divergence Theorem

The second page manages to get the "whole story" on one panel, including a long-winded way of computing the flux of the electric field over a small sphere around a point charge. That we get the same answer as the short-cut we did on Friday once again demonstrates the power of thought over mindless plug-and-chug of formulas.

We reduce Gauss' Formula to Gauss' Divergence Theorem. This has to be demonstrated some other time.

On the third page you will find the algebraic derivation of the divergence of a vector field in cylindrical coordinates. This approach complements the geometric approach taken by Shey. We will do both algebraic and geometric comptutations, also for spherical coordinates.

Watch this space for instructions for next Friday's quiz.

G.Francis