MATH 371 Assignments and Project Spring, 2009




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TEXTS: Fundamentals of Geometry by B. Meserve and J. Izzo, A.W. (1969) - ON LINE through Moodle.
The Elements by Euclid, 3 volumes, edited by T.L. Heath, Dover (1926)
Proof in Geometry by A.I Fetisov, Mir (1978)
Flatland By E. Abbott, Dover.


Tentative assignmentsand topics for classes. 11/24/08 Blue cells Subject to Revisions
Week Monday Wednesday Friday Reading/Videos for the week. Problems 
Due on Wednesday 
of the next week
1  No Class
1-21-09
1.1 Beginnings 

 

1-23
What is Geometry? 
Starting to look at Euclid. Prop 1.

M&I:1.1, 1.2
E:I Def'ns, etc. p153-5; 
Prop. 1-12,22,23,47 
A:.Complete in three weeks
Due:1-30-09
M&I p5:1-8,11
2 1-26 The Pythagorean Theorem 

More on Pythagoras and Euclid.
1-30
Prop 2
Begin  disssection theory,
M&I 1.2, 1.3 
E: I Prop. 16, 27-32, 35-45.
Due: 2-4 
M&I: p10:1,2,5,10,11-13
Prove:The line segment connecting the midpoints of  two sides of a triangle is parallel to the third side and is congruent to one half of the third side.
[ HELP! Proof outline for the midpoint proposition.]
32/2Convexity defined.
Equidecomposable Polygons
Constructions 
Isometries 
1.1 Def'ns- Objects 

 2/4 1.2 Constructions 1.4 Continuity2/6  1.3 Geometry: Constructions and numbers
M&I 1.3,1.4 
E: III Prop. 1-3, 14-18, 20, 21, 10 
Here’s looking at Euclid
F. Sect. 11, 25, 31
Watch Equidecomposable  Polygons
Due: 2-13 (changed 2-13!)
M&Ip11: 16-19, 24, *27  Problem  Set 1

4 2/9 More on continuity and rational points.
2/11
Start Inversion
Orthogonal Circles
2/13More on Cantor
Similar triangles
Odds and ends.
Coordinates.
M&I:1.5, 1.6, 2.1 
E: V def'ns 1-7;VI: prop 1&2 
F. Sect. 32
Due 2-18
M&I: p17: 5, 8-11
p23: 9,10 (analytic proofs)
5 2/16 Odds and ends    2/18 Odds and ends
2/20Start: Transformations - Isometries
Transformations - Isometries.
M&I: 2.1, 2.2
E: V def'ns 1-7;VI: prop 1&2 
E:IV Prop. 3-5
Isometries (Video # 2576 in Library) .
Due: 2-25
M&I:1.6:1-12,17,18 

Problem Set 2
6 2/23More Isometries: Coordinates and Transformations
classification
2/25  More on Isometries
2/27  ....
M&I: 2.1,2.2 Due 3-4
Problem Set 3
(Isos Tri)   [3 Points for every distinct correct proof of any of these problems.]
7
3/2Finish Classification of Planar Isometries.

Begin Affine Geometry

3/4 Isometries and symmetries
3/6 Proportion and Similarity
M&I: 2.2 again;3.1,3.2, 3.5 Quiz #1 on 3/11
See Sample quiz on Moodle.

8
3/9 More on Similarity
3/11 Inversion and Affine Geometry (planar coordinates) the Affine Line. 3/13 Constuctions with Straight edge and compass. M&I:3.6, 3.4,3.7
View video (in Library #4376 ) on "Central similarities" from the Geometry Film Series. (10 minutes)
View video (in Library #209 cass.2) on similarity (How big is too big? "scale and form")  "On Size and Shape"  from the For All Practical Purposes Series. (about 30 minutes)

9 Spring break 3/16
No Class
3/18 No Class 3/20 No Class

10 3/23 Visualizing the affine plane. Seeing the infinite.Affine geometry- Homogeneous coordinates and visualizing the affine plane.
3/25
More on Homogeneous coordinates for the plane.A first look at a "Projective plane."
Axioms, consistency, completeness and models.
3/27Begin Synthetic Geometry [Finite] Algebraic-projective geometry: Points and lines.
Spatial and  Planar
Axioms for 7 point geometry.
Begin Synthetic Projective Geometry
A non-euclidean universe.
M&I :3.1, 3.2, 3.5, 3.6, 3.7; 4.1
Due :  4/1
 M&I: 3.5: 1,3,4,5,10,11
3.6: 3,7-15 
3.7: 1,4,7,10,13
11 3/30 Homogeneous Coordinates with Z2 and Z3
More on Finite Synthetic Geometry and models.
Proof of Desargues' Theorem
4/1 -Projective Geometry -Visual/algebraic and Synthetic..Axioms 1-6 Projective Planes. . 4/3. More on the axioms of Projective Geometry.RP(2) as a model for synthetic geometry.
M&I:4.1, 4.2, 4.3, 2.4
12 4/6 Proofs of some basic projective geometric facts. 4/8 Triangle Coincidences (Perpendicular Bisectors- the circumcenter)
Applications of Projective  Geometry Postulates.1-6
4/10 Quiz #2
Desargue's Theorem and Duality

Due 4/15
M&I: 4.1:7,15,16; 
Prove P6 for RP(2); 
4.2: 2,3, Supp:1 
4.3: 1-6, Supp:1,5,6
13 4/13 Conic Sections.
 More Duality
4/15  More Postulates-
Sections (more duality)
Complete quadrangles
Postulate 9.  
4/17 Perspectivities and Projectivities.
Projective transformations.
Conics
Pascal's Theorem ?
More on coordinates and transformations.
M&I: 
4.5,4.6(p94-97).4.7, p105-108 (Desargues' Thrm)
Watch video: "Conics" [VIDEO #628].
Watch video: For All Practical Purposes on conicsFAPP on conics[HSU Video #209- 3. Stand-up conic (Conic sections) (ca. 30 min.)].
WatchVideo: Orthogonal Projection [Video #4223]

Due : 4/22
Problem Set 4
 
14 4/20Projectivities. Perspective 4/22Transformations of lines with homogeneous coordinates 4/24 Projectivities in 3 space: More on Projective Line Transformations with Coordinates. Begin Harmonic Sets and Construction of Coordinates. 4.10, 5.4, 2.4 
4.11
Due: 4/29
M&I: 4.5:2  ;4.6: 7,8,9;   4.7: 4,7 
4.10: 4,5,9,10
[Prove P9 for RP(2),optional]
15
Final exam available  4/30.
4/27Harmonic sets: uniqueness and construction of coordinates for a Projective Line, Plane, Space.
4/29More on Transformations, Coordinates and Harmonic sets. 5/1 5.1,5.4;,5.2, 5.3,5.5, 5.7, 6.1, 6.2
16
Final projects are due for review Tuesday, May 5th.
5/4 Projective generation of conics
 Pascal's and Brianchon's Theorem.
5/6 Matrices for familiar Planar Projective Transformations.
Inversion angles, circles and lines?
5/8 The Big picture in Summary.




 







Due:
M&I: 4.10:1,3,6,7;
 5.4:1-8,10;  5.5: 2,3,7





Due: 
M&I: 4.10:1,3,6,7; 
5.1:5; 5.4:1-8,10;  5.5: 2,3,7

16
Conics revisited.
Inversion and the final exam.

Quiz #3

 . Student Presentations


Project Proposal Guidelines and Suggestions
The Project. Each student will participate in a course project either  as an individual as a part of a team. Each team will have at most three. These projects will be designed with assistance from myself . The quality of the project will be used for determining letter grades above the C level. Ideas for projects will be discussed during the third week.
Preliminary Project Proposals should be submitted for first review by 5 p.m., February 10th.
A progress report on the project is due March 25th.
Final projects are due for review Tuesday, May 5th. (These will be graded Honors/Cr/NCr.)

A Project Fair will be organized for displays and presentations during the last day of class. Details will be discussed later.


Guidelines for Preliminary Proposals:



Results of Brainstorming and other suggestions from previous courses :)

Tiling patterns - tesselation
3d tiling
MC Escher
perspective
Curves: conics, etc.
optical illusions
knots
fractals
Origami

Kaleidescope
Symmetry
The coloring problem
Patterns in dance and other performance arts
Flatland sequel (4d)

Maps
Juggling
structural Rigidity
dimension
Polyhedra

bridgemaking (architecture)

Models (3d puzzles) paper mache or clay
mobiles
sculpture

A play - movie
build three dimensional shapes
power point
performance
website


Problem Set 1

DEFINITIONS: A figure C is called convex if for any two points in the figure, the line segment determined by those two points is also contained in the figure.
That is, if A is a point of C and B is a point of C then the line segment AB is a subset of C.

If F and G are figures then F int G  is { X : X in F and X  in G }.
F int G is called the intersection of F and G.
If A is a family of figures (possibly infinite), then  int A = { X : for every figure F in the family A, X  is in F }.
int A is called the intersection of the family A.
-----------------------------------------------------------------

1. Prove: If F and G are convex figures , then F int G is a convex figure.

2. Give a counterexample for the converse of problem 1.

3. Prove: If A is a family of convex figures, then int A is a convex figure.

4. Prove: The line segment RS is convex. [ Refer to M & I pg.2.] 


Problem Set 2

1. Suppose n is a natural number. Given P0 and P1 , prove by induction that you can construct with straight edge and compass (SEC) a point P sqrt(n)   which will correspond to the number  sqrt(n) on a Euclidean line.

2. Suppose we are given P0, P1, and P a where P a corresponds to the real number a>0. Give a construction with SEC of a point Psqrt(a) which will correspond to the number  sqrt(a) on a Euclidean line.

3. Given points P0, P1, Px, and Py on a Euclidean line corresponding to the real numbers x>0 and y>0, give constructions with SEC for the following points.

a) P x + y b) P x - y c) P x *y d) P 1/x
4. Construct with SEC on a Euclidean line:   sqrt(5)/sqrt(3)  + sqrt(sqrt(6)) .

5. Suppose that d(A,B) = d(A',B') and that l is the perpendicular bisector of the line segment  AA'. Let B'' be the reflection of B across l, i.e., B''= Tl(B). Prove that if  B' is not equal to B''  then A' lies on the perpendicular bisector of the line segment B''B'.


Problem Set 3

1.  Prove: Two of the medians of an isosceles triangle are congruent.

2.  Prove: If two of the medians of a triangle are congruent then the triangle is isosceles.

3.  Prove: The angle bisectors of congruent angles of an isosceles triangle are congruent.

4.  Prove:  If two of the angle bisectors of a triangle are congruent then the triangle is isosceles. 


Problem Set  4

1. Use an affine line with P0 , P1 , and Pinf given. Show a construction for P1/2 and P2/3.

2. Use an affine line with P0 , P1 , and Pinf   given. Suppose x > 1.
Show a construction for  Px2 and Px3 when Px is known.

3. D is a circle with center N tangent to a line l at the point O and C is a circle that passes through the N and is tangent to l at O as well.
Suppose P is on l and PN intersect C = {Q}; Q' is on C so that Q'Q is parallel to ON; and {P'} = NQ'  intersect l.

Prove: a) P and Q are inverses with respect to the circle D.
b) P' and Q' are inverses with respect to the circle D.
c) P and P' are inverses with respect to the circle with center at O and radius ON.

4. Suppose C is a circle with center O and D is a circle with O  an element of D.
Let I be the inversion transformation with respect to C.

Prove: There is a line l, where I(P) is an element of  l for all P  that are elements of  D -{O}.