Math 4027-Section 1 Information For Spring 2025

Time MWF 12:30 PM -- 1:20 PM
Location Room: 119 Lockett.
Calendar Our class meets from Monday January 13 through Friday May 2. The Final Exam will be Tue., May 6, 5:30 p.m. - 7:30 p.m.
Leonard Richardson Office 386 Lockett

Office Hours

  1. MWF 11 AM -- 12 Noon or 1:30 PM -- 2 PM in person in my office, 386 Lockett Hall.
  2. TTh online only, at this Zoom link: https://lsu.zoom.us/j/7111204773 by arrangement only. Email me if you would like an appointment for online Zoom office hours on Tuesday or Thursday.
I am available at other times. Email first to make sure I'm able meet with you. I answer email many times daily---usually quickly.
Telephone 578--1568
E-Mail rich@math.lsu.edu
Text An Introduction to Ordinary Differential Equations by Earl A. Coddington. This text is available as a Dover Publications reprint for a modest price. There are also used copies available of the original book, which was published in 1961 by Prentice-Hall. This text quickly became a classic, which is why it is available currently as a new Dover paperback. The Dover reprint is a direct copy of the 1961 original.

Graduate Assistant

You will turn in homework in class on the due-date. If you must be absent on the due-date, you may email the scan files of your homework to the grader directly by class time: Mr. Basit Abdulfatai at babdul5@lsu.edu, who will grade those homework problems that are to be turned in---the ones that are assigned in red boldface in the table below.
The grader will be available to answer questions about the homework grading at 383 Lockett Hall Tuesdays from noon - 1:30 PM.
Please be sure to write your solutions neatly and carefully so that they can be read.


Please Note: If you are turning an assignment in by email, the best way to submit an assignment by email is with a device such as a tablet or a drawing board that enables you to write on the computer screen and save or convert to pdf. If you have no such device, you can use a scanner or a phone to photograph your work as jpg images. Then place the images, photographed in the correct order, on your computer screen. Highlight the whole group of pages and select print and then select print or save to pdf. That should make one pdf file with all your pages in order. Thank you.
Prerequisites Math 2057 or 2058, and Math 2085 or 2090. What one needs is 3 semesters of calculus and some linear algebra.
This course does not require prior background in differential equations. That is why it is called an introduction. But it is a 4000-level course because we will pay much more attention to the mathematical structure and foundations of this subject, which is essential in all the pure and applied mathematical sciences and engineering.
Free Math Tutoring Your first resource should be to see me. I look forward to helping students individually in my office. There are also other resources:
The Shell Tutorial Center will open its doors on TBA, in ROOM 141, Middleton Library.
HOURS of Operation: M-Th, 9:30 AM to 7:00 PM. Friday, 9:30 - 3:00 pm.
FOR More information on tutoring in all subjects go to: www.lsu.edu/tutoring.
CAS also offers many on-line student resources such as study tips, time management, etc. CAS is located in B-31 Coates Hall.
CAUTION: There have been reports of unauthorized persons advertising tutoring services on campus and even in classrooms by circulating sign-up sheets. Be careful! The University does not authorize or recommend such services and advertising for such services is not permitted in our classroom. If you see advertising for such services in our classroom, please let me know.

Special Instructions during Public Health or Safety Emergencies

Your health and safety are our top priority. If you are feeling ill please contact the LSU Student Health Center for medical advice. If you are experiencing excessive stress, the Student Health Center offers mental health support as well. And please observe all the University's requirements and recommendations during emergency conditions.

We have learned from recent years that there can be unexpected changes due to the unpredictable nature of emergencies such as pandemics or extremes of weather, so that the format of the course and/or requirements may be forced to change, and if this is the case we will take care to ensure that every student is treated in a fair and considerate manner. If you have any special individual difficulty, please contact me quickly so that I can do anything possible to assist you. That said, we are looking forward to the new semester and hoping that it will be smooth sailing.

With regard to class attendance, if you don't feel well, check with the Student Health Center and follow their advice about whether or not to come to class.

Organization of this Class

Homework will be assigned daily. Please understand that it is from the effort of working your way through assigned problems on paper that you learn mathematics.
It is by no means sufficient to read solutions in a solutions manual! You must work out problems yourself, with paper and pencil, in order to learn this work.
Do not become a victim of the online scoundrels who will sell you solutions for a few dollars a month. They do not care about the quality of your education, and they will not help you if the result is that you need to repeat the course and pay tuition a second time for the same course.
Examination problems will be very similar to assigned homework problems. Thus your daily effort on homework problems will be strongly reflected in your test grades.

Tests and Homework

Tests will be closed-book tests. You must keep your eyes on your own paper and do your own work. Do not communicate with your classmates during an examination. No books or notes are permitted, electronic, paper, or on any other medium. No electronic devices are permitted other than a calculator and a watch to check the time. No cell phones, smart phones, or internet-connected devices are permitted.
The problems will be similar to those in the homework. A correct answer is not sufficient to receive credit. You must show all the work that leads correctly to the solution.
Some of the assigned homework problems (marked in red bold face) will be turned in on the date indicated. These collected assignments will be graded, and your collected assignments will count collectively as a fourth hour test. But remember that the problems on the in-class tests will be based directly on all the assigned problems, not just the collected problems. So if you don't know how to solve an assigned problem, be sure to ask me about it!

Attendance is required.

Your presence and participation in class is an essential part of this course. Most LSU students are conscientious and sensible about coming to class unless there is a serious, excusable reason for not being able to do so. However, there is an unfortunate tendency for some students to become discouraged as the term progresses and to cease regular attendance. This happens despite the fact that a student who is feeling discouraged has an especially great need to be in class and to ask questions. The attendance policy is intended to ensure that every student comes to class even when the going gets tough.
If you need to be absent you must tell me why so that I can determine whether or not such an absence is excused. Depending on circumstances I may require documentation for your absences and documentation will always be required if you are absent from an hour test or from the Final Examination. If you miss a test, it is your responsibility to speak to me as soon as possible to determine whether or not your excuse is acceptable. Here is some General Guidance regarding appropriate reasons for absence from a test or examination. If you are in doubt, ask me as soon as possible.

When should you ask questions?

You should ask questions every time you do not understand something and also every time you are curious about something. Ask questions in class. Be aware that when I am writing on the whiteboard I have no way of seeing your raised hand. So speak up with your questions! Our class size is small so you should view our meetings as a two-way discussion and not a formal lecture. It is a good thing to speak up with your questions!
Ask questions after class. Ask questions in my office hours. Ask questions by email. Please consider this: I have been teaching as a University faculty member for more than half a century. So I ask you to consider that I just may be able to help you with whatever is causing you difficulty if you will permit me to do so. It is a pleasure for me to help each and every student, so please give me a chance to help you to the best of my knowledge and ability. Every single one of you is important to me.

Lateness and Classroom Conduct

Please try to arrive on time for class. But sometimes it may be unavoidable to be late. If you are late, please come right into class, doing so as quietly as you are able so as not to disturb other students. I do not want you to wait outside in the hall. You should have as much classroom time as possible, so please just come in--quietly--and take a seat even if you are late. Class time is a time for work. So when class begins please put away all cell phones, smart phones, head phones, wrist watch communicators, tablets, laptops, etc, and turn your attention to the work of the class. Thank you.

Grades

There will be three hour tests, worth 100 points each, and a two hour final examination, worth 200 points. There will be collected homework problems, marked in red bold face. The collected homework problems will count collectively as if it were a fourth 100-point hour test. Some of the red problems will be starred, and they will be treated as bonus questions because they are harder, so that your homework average could go over 100%! Your lowest hour test grade will be replaced by half of your 200-point final exam score, if it is to your advantage. I will grade your hour tests and your final exam and return the hour tests to you the very next class meeting each time. Our Teaching Assistant will grade your collected homework problems. Your test average will be the sum of all your hour test grades, your final exam grade , and your homework grade as a percentage divided by 6, since 600 will be the maximum possible number of points. The minimum grade for each letter grade is as follows:
A+, 97
A, 93
A-, 90
B+,87
B, 83
B-, 80
C+, 77
C, 73
C-, 70
D+, 67
D, 63
D-, 60
F, below 60
You should save all your graded work for future study and in case you think your final grade is in error.

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Remarks

It is important not to fall behind. It is very important to attend class and participate in homework discussions daily. Please do not assume you can take care of difficulties later---see me for help as soon as possible if there is something you do not understand! You are responsible for all assigned problems---not just those which we go over the next day!

Homework Assignments and Downloads

The table of assignments below needs to be revised for the current semester and for the current 9th edition of our text. You will know an assignment is correct for this semester when the due date has been inserted. Be sure to reload this page from the website each time you visit, since it will be updated daily! Remember, it is only the problems marked in marked in red bold face that will be collected!

You should keep a notebook with all your solutions written out, including those problems that are not collected. We will reserve some class time each day to answer questions about the homework that is due for that day. Test questions will resemble assigned homework problems, so it is important to put in the time and effort to keep up with the daily homework.

The University has clear policies requiring academic honesty. If you email me about a pending assignment, I may send a hint to the whole class in answer to your question, not giving your name of course! If on the other hand you get a good idea from another book, or from talking with a friend, academic honesty requires that you acknowledge your sources openly. Above all, never copy directly from another person's written work as though it were your own. Remember that your own good name is irreplaceable. This is a sound principle which will serve you well throughout your life. Moreover, on a practical level, it is very foolish claim another person's work as your own. Work that is copied can be recognized very easily.

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Due Assignments
January 13 Read this syllabus so you can ask questions about it in class. Obtain a copy of the text so that you are ready to begin work. If you have been away from mathematics courses for a few years, it may be necessary to review what you learned during your earlier courses.
January 15 pp5-6/ 1c-g, 2b,c, 3ace, 4a-d, 6, 7, 8, 9, 10. Remark: Some of these, especially 6-10, may really test your skills with complex arithmetic! Bring questions Wednesday. Note that some of the answers are given in the back of the book. But what matters is to figure out how to get those answers! Remember, it is only the problems marked in red bold face that will be collected!

January 17 Hand in, being sure to show how you got your answers: Pg.6/ 8, 9, 10b. Hints: For 8, square both sides so the modulus squared will be a complex number times its conjugate. For 9, use what we learned today about multiplication of complex numbers in the polar form. For 10b, use the result of 9.
January 22 pp.15-17/ 1-3.

Since the campus is closed this Wednesday, please watch this Recorded Zoom Lesson , which makes up for the missed classtime due to a winter storm.

January 24 pp.15-17/ 4, 7; Also: 5. (The two red boldface questions are to hand in.)
January 27 pp. 19-20 / 1, 3, 5
January 29 pp. 19-20 / 2, 4.
February 3 pp 26-27 / 1, 3c, 5, 7, 8, 9.
February 5 Hand in, being sure to show how you got your answers: pp 26-27 / 4, 6, 10. Also: Pg. 30 / 1, 3.
Februay 7 Pg. 38 / 1, 3, 5.
February 10 Pg. 41 / 1, 2, 6a.
Hand in, being sure to show how you got your answers: ... TBA
Hand in, being sure to show how you got your answers: ... TBA
May 2 TBA Please remember to fill out your course evaluation forms online, before Sunday night.
Bring questions to review for the Final Exam! Don't forget to review from the beginning of the course! Study for the Final Exam! This 200-point exam will cover the whole course in a uniform manner, so remember to review from the beginning of the course. Coverage on the Final Exam runs from the first assignment through the last assigned problem.
Your final grade for the course will be the larger of the following two:
1. The grade guaranteed by the formula provided higher on this page.
2. One letter below the final exam grade. For example, if your final exam grade is A-, you are guaranteed at least a B- in the course.
Thus the final exam provides a safety net that supplements the calculations specified above.
May 5 -- 7 Final Exam Week Office Hours:
I will have office hours TBA

May 6 The Final Exam will be Tues., May 6, 5:30 p.m. -7:30 p.m. in our regular classroom.
May Please download and read carefully the 2025 Final Examination.