Dr. Sarah's Math 2240 Web Page - Spring 2008

Jump down to tomorrow's homework which is located above the red lines
Date     WORK DUE at the beginning of class or lab unless otherwise noted!
May 6 - Tues
  • Final Project Poster Sessions from 9-11:30. Be sure that your poster (one per group) is facing so that it is taller than it is wider and is at most 2 feet wide. Bring your own beverage. If you want to bring something to share, feel free - Dr. Sarah will provide some snacks. peer evaluation, self evaluation
  • Test 3 revisions for a possible +8 due by 1pm. Turn in with your original test. To receive full credit, your revisions must be complete and correct and in addition, if you had an incorrect example for a DNE problem, explain why it should be DNE. I am happy to look over these in office hours before they are due to ensure you receive full credit.
  • April 30 - Wed
  • Final Project Abstract due by 2pm as an ASULearn message or to the ASULearn personal storage space as an attachment I can read (text, Word, rtf, Maple, ...)
  • Come prepared to present your abstract orally in class.
  • A maximum of two people per topic (either as a group or individual projects) will be granted via an ASULearn message.
    Applications of Linear Algebra to Electron Microscopy: Zach Russell
    Chemistry and Linear Algebra: Benjamin Deming
    Computer graphics program which models the movement of the solar system. All calculations (rotations, transformations, scaling, etc...) will be based off of linear algebra calculations in a 3D environment: Jared Beckerman
    Coding and Satellite Encryption and Linear Algebra: Dewey Bustle and Michael Huey
    Cryptology and Linear Algebra: Dustin King
    Contra Dancing and Matrices: Graylyn Byrd
    Fractals and Linear Algebra: Robert McKinnon and Rachel Sigmon
    Game Theory, Linear Algebra, and Tic Tac Toe: Lateef Livers and Arthur Wofford
    Gaussian Elimination in Java: Hung Pham and Bobby Tokajer
    Genetically Inherited Traits and Diseases: Lianna Beard
    Genetic Algorithms: Aaron Folstad
    Gershgorin Circle Theorem and Applications to Flutter of an Aircraft: David O'Connor
    History of Linear Algebra: Mandi McGaha and Kimberly Eckard
    Linear Programming: Ben Thompson
    Matrix Applications in Optics: Ashley Roberts
    NFL Rates the Passing Ability of Quarterbacks: Chris Depenbrock
    Robotics, Matrices, and Linear Algebra: Jessie Goodrum and Terry Jordan
    The use of Linear Algebra in search engines on the web: Jonathan Hearing
  • __________ ________________________________________________________________________
    __________ ________________________________________________________________________
    April 23 - Wed
  • Meet in 205.
  • Test 3 study guide
  • Test 2 revisions due for a possible +3. Turn in with your original test.
  • April 21 - Mon
  • Review for test 3 and write down any questions you have.
  • April 16 - Wed
  • Problem Set 6 - See Problem Set Guidelines and Sample Problem Set Write-Ups
    Note: You may work with two other people and turn in one per group of three
    Problem 1:  7.1   #14 by hand and on Maple via the Eigenvectors(A); command also compare your answers and resolve any apparent conflicts or differences within Maple text comments.
    Problem 2:  Rotation matrices in R2   Recall that the general rotation matrix which rotates vectors in the counterclockwise direction by angle theta is given by
    M:=Matrix([[cos(theta),-sin(theta)],[sin(theta),cos(theta)]]);
      Part A:   Apply the Eigenvalues(M); command. Notice that there are real eigenvalues for certain values of theta only. What are these values of theta and what eigenvalues do they produce? Also find a basis for the corresponding eigenspaces. (Recall that I = the square root of negative one does not exist as a real number and that cos(theta) is less than or equal to 1 always.)
      Part B:   Use only a geometric explanation to explain why most rotation matrices have no eigenvalues or eigenvectors.
    Problem 3-5:  7.2   7, 18, and 24
    Problem 6:  Foxes and Rabbits (Predator-prey model)
    Suppose a system of foxes and rabbits is given as:


      Part A: Write out the Eigenvector decomposition of the iterate xk, where the foxes Fk are the first component of this state vector, and the rabbits Rk the second.
      Part B: Use the decomposition to explain what will happen to the vector xk in the longterm, and what kind of vector(s) it will travel along to achieve that longterm behavior.
      Part C: Determine a value to replace 1.05 in the original system that leads to constant levels of the fox and rabbit populations (ie an eigenvalue of 1), so that eventually neither population is changing. What is the ratio of the sizes of the populations in this case?
  • April 9 - Wed
  • Review the projection Matrix([1/2, 1/2],[1/2,1/2]]); from the ASULearn geometry of eigenvectors demo.
  • Skim class notes from Monday.
  • Apr 7 - Mon
  • Begin working on the final project. See the project link under the May 6 date and the abstract link under the April 30 date. Your project topic and group (1 or 2 people) must be approved by Dr. Sarah as a message on ASULearn. Topics will be assigned on a first-come, first-served basis.
  • Apr 2 - Wed
  • Meet in 205. Review two demos - Geometry of Eigenvectors and Foxes and Rabbits - on ASULearn and write down any questions you have.
  • March 31 - Mon
  • Meet in 205.
  • Test 2 on Chapters 1-3 and 4. study guide
  • Test 1 revisions due for possible +3. Turn in with the original test 1.
  • March 26 - Wed
  • Look over ASULearn solutions and review for test 2 (see study guide) and write down any questions you have.
  • Bring test 1 to class.
  • March 19 - Wed
  • Meet in 205
  • Problem Set 5 - See Problem Set Guidelines and Sample Problem Set Write-Ups
    Note: You may work with two other people and turn in one per group.
    Hints and Commands for PS 5
    Problem 1: 4.4   16
    Problems 2-3: 4.5   24, 48
    Problem 4: Cement Mixing Continued (**ALL IN MAPLE**) This problem is worth more than the others
    Problems 5-6: 4.6   24, 27
  • March 17 - Mon
  • Practice Problems (to turn in)
    4.4   11, 53
    4.5   22
    Problem 2 of the group work
  • Work on Problem Set 5
  • March 5 - Wed
  • Meet in 205
  • Problem Set 4 See Problem Set Guidelines and Sample Problem Set Write-Ups
    Note: You may work with two other people and turn in one per group.
    Hints and Commands for Problem Set 4
    Problems 1-2: 4.1 36 and 44
    Problem 3:  Cement Mixing (*ALL IN MAPLE*) *This problem is worth more than the others.
    Problems 4-7: For all of the following vector space and subspace problems: If it is a vector space or subspace, then just state that it is, but if it is not, then write out the complete proof that one axiom is violated as in class:
    4.2   22
    Natural Numbers   Prove that the natural numbers is not a vector space using axiom 6.
    True or False:   The line x+y=0 is a vector space.
    Solutions to the plane 2x-3y+4z=5, ie {(x,y,z) in R^3 so that 2x-3y+4z=5}   Prove that this is not a subspace of R3 using axiom 1.
    Problem 8: 4.3   (14 part D be sure to leave n as general as in class - do not define it as 2x2)
  • March 3 - Mon
  • Practice Problem (to turn in)
    4.2 21
  • Feb 27 - Wed
  • Timeline Extra Credit Project
  • Bring your book to class.
  • Feb 25 - Mon
  • Look at the Timeline Extra Credit Project due Wed Feb 27.
  • Begin Problem Set 4 due on Wed March 5.
  • Bring your book to class.
  • Feb 20 - Wed
  • Meet in 205
  • Test 1 on Chapters 1, 2 and 3 study guide
  • Feb 18 - Mon
  • Practice Problems (to turn in)
    4.1 7, 35, 43, 49, 52
  • Review for test 1 and write down any questions that you have via the study guide.
  • Feb 13 - Wed
  • Meet in 205
  • Problem Set 3 See Problem Set Guidelines, Sample Problem Set Write-Ups
    Note: You may work with at most two other people and turn in one per group.
    Maple Commands and Hints for PS 3
    Problem 1: 2.5   24
    Problem 2: Healthy/Sick Workers (all on Maple including text comments) *This problem is worth more than the others.
    Problem 3: 3.1   47 part a
    Problem 4: 3.2   32 part c
    Problem 5: 3.3   (28 by-hand and on Maple)
    Problem 6: 3.3   (34 if a unique solution to Sx=b exists, find it by using the method x=S^(-1) b)
    Problem 7: 3.3   (50 parts a & c)
  • Feb 11 - Mon
  • Practice Problems (to turn in). Do not worry about getting the same answer as the back of the book (although it would be nice!) but do concentrate instead on making sure you understand the determinant methods. Do not worry about explaining your work.
    2.5 number 10. We set this up in class and saw that the first column of N represented A->A, A->B, and A->Neither [.75, .20, .05 is the first column; .75, .15, .10 is the first row]. Using regularity, we can see that the system will stabilize since the columns add to 1, and the entries are all positive. Find the steady-state vector by solving (N-I)x=0 for x.
    3.1   33 by-hand using the co-factor expansion method. Expand along the first column to take advantage of the 0s, and then the 1st column of the next 4x4 matrix, and then the 3rd row of the 3x3 matrix.
    3.2   25 by-hand using some combination of row operations and the co-factor exapansion method.
    3.3   31
  • Feb 6 - Wed
  • Meet in 205
  • Problem Set 2 - See Problem Set Guidelines and Sample Problem Set Write-Ups
    Maple Commands and Hints for PS 2
    Note: You may work with at most two other people and turn in one per group but each person must complete and turn in Problem 5 themselves (in their own words).
    Problem 1: 2.1   30
    Problem 2: 2.2   (34 parts a, b & c)
    Problem 3: Show that the following statements about matrices are false by producing counterexamples and showing work:
          Statement a) A2=0 implies that A = 0
          Statement b) A2=I implies that A=I or A=-I
          Statement c) A2 has entries that are all greater than or equal to 0.
    Problems 4-7: 2.3   12, (14 by hand and on Maple), (28 part a - look at the matrix system as Ax=b and then apply the inverse method of solution), and     (40 part d)
  • Feb 4 - Mon
  • Practice Problems in 2.1 and 2.2: (to turn in). Do not worry about getting the same answer as the back of the book (although it would be nice!) but do concentrate instead on making sure you understand the methods. Do not worry about explaining your work.
    2.1 (by-hand: 9, 32)
    2.2 (by-hand: 17, 18), (35 use matrix algebra to combine the elements, set it equal to the other side, use matrix equality to obtain equations, and solve using the ReducedRowEchelonForm command on Maple. No need to print out your Maple work - just summarize it on your homework.)
  • Work on Problem Set 2
  • Jan 30 - Wed
  • Read through Sample Problem Set Write-Ups
  • Problem Set 1 - See Problem Set Guidelines, Sample Problem Set Write-Ups, and Problem Set 1 Maple Commands and Hints. I also encourage you to ask me questions about anything you don't understand in office hours or on the bulletin board. Your explanations must distinguish your work as your own.
    Note: You may work with at most two other people and turn in one per group but each person must complete and turn in Problem 3 themselves (in their own words).
    Problems 1-2: 1.1 60 b and c, 74,
    Problems 3-5: 1.2   (30 by hand and also on Maple), 32, (44 find all values of k and justify),
    Problems 6-7: 1.3   24 a and b, 26
  • Jan 28 - Mon
  • Compare your 1.1 practice problems with solutions on ASULearn. A similar style of explanation is necessary for problem set 1 but not for practice problems.
  • Do these by-hand since you need to get efficient at the by-hand method. No need to write in complete sentences.
    1.2   15, 25, 27, (43 find all the values of k and justify why these are all of them), and 49. Do not worry about getting the same answer as the back of the book (although it would be nice!) but do concentrate instead on making sure you understand the method of Gaussian Elimination.
  • Read through Problem Set Guidelines and Problem Set 1 Maple Commands and Hints Continue working on problem set 1.
  • Jan 23 - Wed
  • Practice Problems to turn in - the answers to odd problems are in the back of the book and there is a student solution manual in mathlab (M-Th, 2-5)
    1.1   7, 15, 19, (59 parts b and c - if it is false, provide a specific counterexample, if it is true, quote a phrase from the text), and 73.
  • Begin working on problem set 1 under next Wed due date.
  • Jan 16 - Wed
  • Read through the online syllabus carefully. Search google for Dr. Sarah, click on her page, and click on the MAT 2240 link and then the Syllabus link. Prepare to share something you read there and write down any questions you have - the university considers this a binding contract between us.
  • Begin working on practice problems for next week under that due date.