Differential Equations

Math 23 Spring 2024


Instructor Tongtong Li
Section 1
Longmei Shu
Section 2
Class MWF 10:10 - 11:15 am Kemeny 007 MWF 2:10 - 3:15 pm Kemeny 007
x-hour Th 12:15 - 1:05 pm Kemeny 007 Th 1:20 - 2:10 pm Kemeny 007
Contact tongtong.li@dartmouth.edu longmei.shu@dartmouth.edu
Office Hours Kemeny 200: Tu 4:00 - 5:00 pm, X-hour
if not used, or by appointment.
Kemeny 211: MWF 10:30 - 11:30 am,
or by appointment.


General Information

Please see Lecture Plan for detailed information.

In person lectures

All lectures will be held in person unless otherwise stated. They will not be recorded. If you are not feeling well or cannot come to class, please contact the instructor prior to class.

In person and remote office hours

Office hours will generally be held in person. Individual appointments with instructors may be held remotely via zoom.

Math 23 tutorial sessions

Tutorial sessions are every Sunday, Tuesday and Thursday from 7-9 pm in Kemeny 201 offered by Jessica Rattray (jessica.rattray.gr@dartmouth.edu).


The course grade will be based upon on weekly homework (total 120 points), exam 1 (100 points), exam 2 (120 points), exam 3 (160 points). Total points possible: 500.

Violations of the Academic Honor Principle will be referred to the the Committee on Standards. In particular please be aware of rules regarding plagiarism and collusion.

Exams 380 points

Here are some old past exams given in previous terms. Please note that these are only meant to be used as practice problems. You should not draw any conclusions about the topics, problem structure, or level of difficulty from them. Working the problems at the end of each section and carefully reviewing your class notes is a great way to prepare for exams.

All time conflicts should be brought to the attention of your instructor as soon as you are aware of them.

Homework 120 points

Homework reinforces concepts and skills while challenging students to extend what they have learned to other types of problems. Because it is important for students to have this experience, instructors will not solve assigned homework problems during office hours before the due date. We will of course answer questions you may have in approaching problems that give you difficulty. It is therefore essential to begin homework sets early so that you may get help if difficulties do arise.

Written homework is assigned weekly and posted on Canvas Assignments page. It is due each Tuesday before 11 pm (East coast time). As all homework is posted well in advance, no late homework will be accepted. Homework typically covers course material through the previous Friday.

Homework grading policy: The goal of homework is to lear to work through problems. Therefore, each problem set will be assigned a grade on a 15-point scale as submitted through Gradescope. The lowest homework score will be dropped, and the combination of the remaining scores will be out of 120 points.

Honor Principle

We will strictly enforce Dartmouth's Academic Honor Principle.

On Exams: Giving and/or receiving assistance during an examination violates the Academic Honor Principle.

On Homework: Collaboration is both permitted and encouraged, but it is a violation of the honor code for someone to provide the answers for you.


Elementary Differential Equations and Boundary Value Problems (11th Edition) by Boyce & DiPrima, Wiley 2017. It is fine to use the 9th, 10th or 12th edition. The problems may differ at the end of each section, but the content is primarily the same. You may find online versions of some older editions.

ORC Course description

This course is a survey of important types of differential equations, both linear and nonlinear. Topics include the study of systems of ordinary differential equations using eigenvectors and eigenvalues, numerical solutions of first and second order equations and of systems, and the solution of elementary partial differential equations using Fourier series.


Mathematics 13 (Calculus of vector-valued functions)


Students with learning, physical, or psychiatric disabilities enrolled in this course that may need disability-related classroom accommodations are encouraged to make an office appointment to see your instructor before the end of the second week of the term. All discussions will remain confidential, although the Student Accessibility Services office may be consulted to discuss appropriate implementation of any accommodation requested. At such a meeting please provide your instructor with a copy of a disability registration form, which lists the accommodations recommended for the student by Student Accessibility Services within the Academic Skills Center. The person you might want to contact at the Academic Skills center is Ward Newmeyer, Director of Student Accessibility Services 205 Collis Center - (603) 646-9900.

Student Religious Observances

Some students may wish to take part in religious observances that fall during this academic term. Should you have a religious observance that conflicts with your participation in the course, please come speak with your instructor before the end of the second week of the term to discuss appropriate accommodations.