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Math 402, Section D13, Fall 2008


Assignment #1 (25 points) - due Wed. Sept. 3 at the beginning of class.
Read Sections 1.1, 1.2, 1.4
Read the Wikipedia articles on Euclidean geometry and non-Euclidean geometry at http://en.wikipedia.org/wiki/Euclidean_geometry and http://en.wikipedia.org/wiki/Non-Euclidean_geometry
Turn in Exercises 1.4.1, 1.4.3, 1.4.4, 1.4.5, 1.4.13


Assignment #2 (30 points) - due Wed. Sept. 10 at the beginning of class

Read Sections 1.5, 1.6

Turn in Exercises 1.5.4, 1.5.6, 1.5.7, 1.5.8, 1.5.9, 1.5.10


Assignment #3 (30 points) - due Wed. Sept. 17 at the beginning of class. Solutions will be handed out in class that day, since the following class is the first test.

Read Sections 2.1 and 2.2

Turn in Exercises 1.6.8, 1.6.9, 1.6.10, 1.6.11, 1.7.1 (you are not asked for proofs. Give experimental evidence from working with Geometry Explorer. You can print out diagrams from Geometry Explorer, or sketch by hand what you see on Geometry Explorer).


Test #1 will be Fri., Sept. 19, in class, covering all of Chapter 1 (except 1.3, which we are skipping), and Assignments #1-3.


Assignment #4 (25 points) – due Fri. Sept. 26 at the beginning of class.

Turn in Exercises 2.1.6, 2.1.7, 2.1.8, 2.1.9, 2.1.10


Assignment #5 (30 points) – due Fri. Oct. 3 at the beginning of  class.
Read Sections 2.4 (through p. 77), 2.5, 5.1

Turn in Exercises 2.5.1, 2.5.4, 2.5.5, 5.1.4, 5.1.5, 5.1.9


Assignment #6 (30 points) – due Fri. Oct. 10 at the beginning of class.

Read Sections 5.2, 5.3. 5.4  We’ll be going through these somewhat quickly, but you need a good understanding of the main points.

Turn in Exercises 5.1.6, 5.2.4, 5.2.11, 5.2.12, 5.3.4, 5.3.5


Test #2 will be Wed., Oct. 15, in class, covering Sections 2.1, 2.5, 5.1, 5.2, 5.3 and Assignments #4-6.


Assignment #7 – due Wed. Oct. 22 at the beginning of class.

Read Sections 5.6, 7.1, 7.2.  Review the Wikipedia article on non-Euclidean geometry. Take a glance at 7.3 just to see what sorts of theorems are proved (we’ll be going into much more detail in class).

Turn in the following exercises:

1. Exercise 5.4.7

2. Exercise 5.6.5

For 3.-6., decide whether each of the following is a subgroup of the group of all isometries.  You don’t have to prove everything, but at least give some reasoning for each of the properties.  We’ll be discussing in class what degree of rigor is required, so come to class!

3. all translations (and the identity)

4. all reflections (and the identity)

5. all rotations (and the identity). Do not assume the rotations all have the same center!

6. all glide reflections (and the identity)

 

7. Give another example of a subgroup of the group of all isometries.

 

8. Answer the following True/False questions concerning the development of non-Euclidean (hyperbolic) geometry. Explanation not required, but be sure you understand it.

a. The system consisting of Euclid’s postulates I, II, III, IV is complete (after a few necessary modern additions such as Pasch’s axiom, to fill gaps left by Euclid).

b. The system consisting of Euclid’s postulates I, II, III, IV, V is complete (after a few necessary modern additions such as Pasch’s axiom, to fill gaps left by Euclid).

c. Euclid’s postulate V is independent of the first four of his postulates.

d. Postulate V can be proved from the first four postulates.

e. The system consisting of Euclid’s postulates I, II, III, IV, ~V is consistent.

f. Saccheri and Lambert were seeking to develop a new geometry.

g. Although Saccheri and Lambert discovered important theorems in hyperbolic geometry, they did not realize that hyperbolic geometry was a new, consistent geometry.

h. Gauss, Bolyai and Lobachevsky all came to believe that hyperbolic geometry was consistent.

i. Gauss used the axioms of hyperbolic geometry to prove that  hyperbolic geometry is consistent.

j. There is exactly one model of hyperbolic geometry.

k. Euclidean geometry is the actual geometry of the physical world.  Hyperbolic geometry and other geometries, while they are interesting axiomatic systems, are unrelated to the physical world.


Assignment #8 – due Fri. Oct. 31 at the beginning of class. (If you are going to put homework in my mailbox, you need to do this by 11am on the due date!)

 

Time to starting thinking about your project for this class (http://www.math.uiuc.edu/~kmortens/402-Fa08/project.htm) Project topics are due Nov. 5.

 

Read Section 7.3 and turn in the following exercises:

7.3.1, 7.3.2, 7.3.3, 7.3.11, 7.3.12, 7.3.13


Assignment #9 – due Fri. Nov. 7 at the beginning of class. (If you are going to put homework in my mailbox, you need to do this by 11am on the due date!)

Using Geometry Explorer, work through Section 7.4 (excluding exercises 7.4.1, 7.4.2). Answer the following questions:

1.      Out of all the Saccheri quadrilaterals you constructed, what was the smallest summit angle measurement? Sketch a picture of the quadrilateral (or print out).

2.      Out of all the Saccheri quadrilaterals you constructed, what was the largest summit angle measurement? Sketch a picture of the quadrilateral.

3.      Use Geometry Explorer to construct various omega triangles and measure the angle sum. Record your results. (Remember there are only two angles – the one on the boundary is not an angle since the two lines do not actually intersect in hyperbolic space.)

4.      Use the Exterior Angle Theorem for Omega Triangles to prove that the angle sum of an omega triangle is always less than 180 degrees. (this problem doesn’t use Geometry Explorer.)

5.      Use Geometry Explorer to construct a line in hyperbolic space and a point not on the line. Then use Geometry Explorer to construct the two limiting parallels (see page 436). Just turn in a sketch or two of your work.

6.     Use the same notation as exercise 7.3.11 for h and a(h). Use Geometry Explorer to construct many pictures of the type shown in the picture accompanying this exercise (you can construct just one and then drag around P and Q to get others). For each, measure h and a(h) and make a chart of these values. What patterns do you see in the chart? Any guesses on a formula for a(h) in terms of h?


Test #3 – Wed. Nov. 12 in class.  This test will cover Sections 5.4, 5.6, 7.1, 7.2, 7.3, 7.4, Assignments #7, 8, 9


Wed. Nov. 19 - Submit a list of references and an outline of your paper.  You should have at least one reference (preferably more!) which is not a webpage. Visit the Mathematics Library in Altgeld Hall.


Assignment #10 – due Fri. Nov. 21 at the beginning of class.

Read Sections 7.5, 7.6 and 7.7.  Turn in the following exercises: 7.5.4, 7.5.6, 7.5.7, 7.5.8, 7.5.9, 7.5.13