We will synchronize our nomeclature. Although this is the fourth week that webpages are displayed for the course, it is, in fact the Fifth Week. So next week will be officially week 6 of the semester.

The first page this week explains how to derive the divergence of a vector field in spherical coordinates. Two of the three steps are left as collectable homework for Wednesday, 18feb98.

The second page covers some examples where the work involved in understanding the divergence in non-Cartesian coordinates has some payoff. We are actively looking for even more esoteric coordinate systems, provided they are scientifically meaningful.

The solution to last Friday's quiz is given on the first half of page 3. The second half shows that in this particular example, we can solve for the flux directly. And, the integrals obtained are identical with the ones obtained using the divergence theorem. In this way, this example is a verification of Gauss' Divergence Theorem, which will concern us for the remainder of the week.

The quiz for this week is take-home. I will distribute a problem set which is due on Monday at class time. I will expect exemplary presentation as well as correct solutions. There is no time pressure on a take-home, so you can make the document look good. Further instructions will be given in class on Friday.

The midterm is scheduled for Friday, 6 March. Please do not schedule yourself to be out of town that day.

G.Francis