Math 5378

Problem Set 11

Due Friday, April 19, 2002, at the beginning of class. Reminder: I will be out of town April 15-18, and there will be no office hours till Friday, April 19. The Monday class will be taken over by Prof. Adams, while the Wednesday class will be rescheduled as a review session before the second midterm.

Study Sections 6.3, 5.1, and 5.2 (through p. 159, Example 2.1) and solve the following problems.

Section 6.3:    2

Section 5.1:    2, 3, 6 (The "if" part only; the "only if" part was on the previous homework), and 8

Section 5.2:    1, 2, 3

1. For a torus, the parallels u=0, u=pi/2, and u = pi are called the maximum parallel, the topmost parallel, and the minimum parallel, respectively. Check which of these parallels are geodesics and which are lines of curvature.

2. Intersect the cylinder x^2 + y^2 =1 with a plane passing through the x axis and making an angle theta with the xy plane. Show that the interscting curve is an ellipse C. Compute the geodesic curvature of C in the cylinder at the points where C meets its axes.