﻿ Math109Spring2019

Math 201, Fall 2019

Instructor:        Jingjun Han

TA:                 Daniel Fuentes-KeuthanEmily QuinanYujie Luo
Office:                Krieger 220
Office Hours:     MW 10:50-11:50 AM, W 3:00-4:00 PM in Krieger 220
Email:                 jhan@math.jhu.edu
Lectures:             MWF 10-10:50 Maryland 110
Textbook:           Linear Algebra with Applications, 5th Edition, Otto Bretscher, Prentice Hall, December 2012

Midterm 1:  Friday Oct 4, 10-10:50
Midterm 2:  Friday Nov 8, 10-10:50
Final         :  Monday Dec 16, 9-12

Homework. The solutions are provided by Daniel Fuentes-Keuthan (HW1, HW4, HW7,HW10), Emily Quinan (HW3, HW 6, HW9,HW12)Yujie Luo (HW2, HW5, HW8,HW11)

HW1. 1.1: 9, 11,15,20,21                           optional: 1.1:41,45,47,49.    Solution.

HW2. 1.2: 5,38,47; 1.3: 4; 1) If a linear system has exactly one solution, show that the number of variables is less than or equal to the number of equations. Provide an example such that the number of variables is equal to (less than) the number of equations, respectively. 2) A linear system with fewer equations than unknowns (n<m) has either no solutions of infinitely many solutions. Provide an example such that the linear system has no solution (infinitely many solutions.).           optional: 1.2: 4,7,48; 1.3: 10,13,19,24,27,28,37,46,52,69.

HW3. 1.3: 47; 2.1: 7,13,50; 2.2:29. Optional: 2.1:1,3,5,32,40,44,48,53. Solution.

HW4. 2.2: 5,12; 2.3: 14,32,81.                             Optional: 2.2: 10,14,33,38; 2.3:1,3,13,65,66,84,85. Solution.

HW5. 2.4: 30, 54; 3.2: 6;

1. Show that a square matrix A is invertible if and only if ker(A) is the zero vector.

2. Let w1=(a,b), w2=(c,d) be two vectors, such that they are not in the same line. Find x,y,z,t such that e1=xw1+yw2,e2=zw1+tw2, where e1=(1,0), e2=(0,1).

Optional: 2.4: 8, 20, 29, 32, 33, 44,68,69,76; 3.1: 7, 21, 42, 50; 3.2: 3, 5, 7.     Solution.

HW6. 3.2: 37; 3.3: 28, 33; 3.4:38, 58.                                           optional: 3.2 :36, 42, 48, 54; 3.3: 22, 29, 33, 39; 3.4: 19, 41, 52, 54, 56, 69, 80. Solution.

HW7. 4.1: 40, 54; 4.2: 10, 55, 67.                                                 optional: 4.1: 19, 25, 27, 41, 60; 4.2: 4, 5, 11, 52, 63, 68, 69, 71. Solution.

HW8. 4.3: 4, 40, 59, 60, 68.                                                          optional: 4.3: 3, 5, 20, 38, 48, 54, 61, 66, 70, 71.  Solution.

HW9. 5.1: 16, 23. 5.2: 8, 28, 35.                                                   optional: 5.1: 8, 11, 12, 17, 18, 21, 31; 5.2: 31, 32, 33, 38, 45. Solution.

HW10. 5.3: 27,33,45,46,60.                                                          optional: 8, 32, 44, 48, 55, 66, 67, 69, 71, 73, 74.

HW11. 5.4: 10, 15, 20. 6.1: 42, 56                                                 optional: 5.4: 1, 11, 12, 21, 28, 35. 6.1: 45, 48, 50, 53, 57. Solution.

HW12. 6.2: 29, 30, 31.  6.3: 25, 26                                                optional: 6.2: 33, 38, 42, 45, 50, 51, 61, 69, 70. 6.3: 30,31,34,41,35. Solution.

Practice Final, Solution: Problem 1-6, Problem 7

Your grade for this course will be calculated as the weighted average of your grades on the weekly homework assignments (20%, lowest HW grade dropped), two midterms (20% each), and a final exam (40%).

The exams in this course will be difficult.

There will be no curve for the class and the final grade will only depend on your position in the class. In usual, A: 30%-40%, B: 30%-40%.

Please bring your ID to all exams. Exams must be completed in blue or black pen. The use of textbooks, notes, and calculators will not be permitted.

No make-up exams will be offered in this course. If you have to miss an exam for a documented, legitimate reason, then your final grade will be calculated using your final exam. Excused absences from midterms will only be permitted with a letter from the Academic Advising Office. No excused absences are allowed from the final exam. If you have conflicts on the final exam, the department will notify you the adjusted dates to take the final exam.

TA’s office hour: Daniel Fuentes-Keuthan Monday 2-3 pm, Yujie Luo Thursday afternoon 4pm-5pm, Emily Quinan Mondays from 1:30-2:30pm.

Homework:

Problem sets will generally be posted here each week before Friday (start from the first week), and you need to submit it in the section next week. The following rules apply to homework:

• Homework is due at the beginning of class, stapled and with name and section number written at the top of the first page.  Late homework will not be accepted.
• Studying in groups are encouraged, but homework has to be written down independently. Copying is not allowed.
• Write clearly and be organized. The grader might choose not to grade your homework if it is too messy.
• To receive full credit for a solution, it is not enough to simply write down the correct answer. You must show all relevant work in an organized fashion.
• The lowest homework score will be dropped.

Special aid:
Students with disabilities or other special needs that require classroom accommodation or other arrangements must let the instructor know at the beginning of the semester.

• Office hours from both the instructor or the TAs are a first source of extra help
• Math help room (Krieger 213): open from Monday-Thursday 9am-9pm and Friday 9am-5pm

General policies:

• No cellphones or computers in class. Calculators are not allowed in exams. You can use calculators in HW.
• The course will pick up its pace gradually. As such, it will be very easy to fall behind, even from missing a single class. Please do not be late for the lecture and recitation.
• If a student is found responsible through the Office of Student Conduct for academic dishonesty on a graded item in this course, the student will receive a score of zero for that assignment, and the final grade for the course will be further reduced by one letter grade.

Ethics:
The strength of the university depends on academic and personal integrity. In this course, everyone must be honest and truthful. Violations include cheating on exams, plagiarism, reuse of assignments without permission, improper use of the internet and electronic devices, unauthorized collaboration, alteration of graded assignments, forgery and falsification, lying, facilitating academic dishonesty and unfair competition. Ignorance of these rules is not an excuse.