**Math 201, Fall 2019**

Instructor: Jingjun Han

TA: Daniel Fuentes-Keuthan，Emily Quinan，Yujie 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, ***5*^{th}* 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; Solution.

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 Midterm1, Solution. Midterm1, Solution.

Practice Midterm2, Solution. Midterm2,
Solution.

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

**Your grade**

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.

Graded
exams will be returned in section. When you receive a graded exam, please take
the time to review the grading and scoring to confirm that no errors have been
made. Do this before you leave the classroom. If you take your exam out of the
room, it will be assumed that you accept the grade, and under no circumstances
will the grade be changed. If you need additional time, please return your exam
to your TA and schedule a time to continue your review. If you want to regrade
the exam, TA will regrade **ALL** of the
problems in the exam, and it is not always the case that you will receive a
higher grade.

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.

For more information see the guide on "Academic Ethics for Undergraduates" and the Ethics board website (http://ethics.jhu.edu) for more information.

In this course, as in many math courses, working in groups to study particular problems and discussing theory is strongly encouraged. Your ability to talk mathematics is of particular importance to your general understanding of mathematics. You can discuss with other students about how to approach the problem. However, you must write up the solutions to the homework problems individually and separately. If there is any question as to what this statement means, please see the instructor or the TAs.