[BUG] Valley Lab

[Tevian Dray]

I'm teaching vector calculus in the Honors College again this year, and had an
interesting experience in the valley lab.  The first part of the activity asks
students to compute B dot drvec along radial lines, then again along circular
arcs.  Almost all of the students did the first computation in rectangular
coordinates, and the latter in polar coordinates.  (One group did both in
polar coordinates.)

This is an interesting change from our early experiences: We originally asked
the questions in the opposite order (and only gave B in rectangular
coordinates), and almost everyone would try to do the circular arcs in
rectangular coordinates.  Yes, I'm probably pushing polar coordinates more now
than I used to, especially in this class.  And B is now given in both
rectangular and polar coordinates.  But it is interesting that students don't
immediately see the connection between radial lines and polar coordinates.
OK, OK, they're not round, but even so.

Tevian