Differential Equations — Mathematics 23, Fall 2026

Section 1 — Feng Fu

Time block: 10A
Classes: Tuesday / Thursday, 10:10 a.m.–12:00 p.m., Kemeny Hall 007
X-hour: Friday, 3:30–4:20 p.m., Kemeny Hall 007
Email: feng.fu@dartmouth.edu

Lecture calendar · Homework and quizzes · Exams · Grading

This tentative plan follows the revised Tuesday/Thursday lecture sequence. Multiple topic decks may be taught in one class. Textbook references use Ch. numbering from the 11th edition. Updates will be announced in class or on Canvas.

Detailed lecture plan

All dates below are in 2026. Homework rows are deadlines or release dates, not additional class meetings. Thursday quizzes are given during class; Friday x-hours are separate from those quizzes. Homework submission details are posted on Canvas.

Section 1 lecture calendar, assignments, quizzes, and exams
Date / meeting	Lecture topics / textbook	Homework / quizzes
Tue, Sep 15 Class 1	Lecture 1: Introduction and classification Ch. 1.1–1.3	—
Thu, Sep 17 Class 2	Lecture 2: First-order linear equations Ch. 2.1 Lecture 3: Separable equations and existence-uniqueness Ch. 2.2, 2.4	—
Fri, Sep 18 Homework	Homework assignment / deadline	PS 1 assigned · Ch. 1.1–2.1
Tue, Sep 22 Class 3	Lecture 4: Modeling with first-order equations Ch. 2.3	—
Thu, Sep 24 Class 4	Lecture 5: Autonomous equations and population dynamics Ch. 2.5 Lecture 6: Exact equations and integrating factors Ch. 2.6	Quiz 1 · during class
Fri, Sep 25 Homework	Homework assignment / deadline	PS 1 due PS 2 assigned · Ch. 2.2–2.5
Tue, Sep 29 Class 5	Lecture 7: Second-order equations and the Wronskian Ch. 3.1–3.2	—
Thu, Oct 1 Class 6	Lecture 8: Complex characteristic roots Ch. 3.3	Quiz 2 · during class
Fri, Oct 2 Homework	Homework assignment / deadline	PS 2 due PS 3 assigned · Ch. 2.6, 3.1–3.3
Mon, Oct 5 Exam	Midterm 1 6:00 p.m. · Location: TBD	—
Tue, Oct 6 Class 7	Lecture 9: Repeated roots and reduction of order Ch. 3.4 Lecture 10: Undetermined coefficients Ch. 3.5	—
Thu, Oct 8 Class 8	Lecture 11: Variation of parameters Ch. 3.6 Lecture 12: Systems and matrix review Ch. 7.1–7.2	Quiz 3 · during class
Fri, Oct 9 Homework	Homework assignment / deadline	PS 3 due
Tue, Oct 13 Class 9	Lecture 13: Linear algebra and eigenvectors Ch. 7.3 Lecture 14: Theory of linear systems Ch. 7.4	—
Thu, Oct 15 Class 10	Lecture 15: Systems with real eigenvalues Ch. 7.5	—
Fri, Oct 16 Homework	Homework assignment / deadline	PS 4 assigned · Ch. 3.4–3.6, 7.1–7.5
Tue, Oct 20 Class 11	Lecture 16: Systems with complex eigenvalues Ch. 7.6 Lecture 17: Fundamental matrices Ch. 7.7	—
Thu, Oct 22 Class 12	Lecture 18: Repeated eigenvalues Ch. 7.8 Lecture 19: Nonhomogeneous linear systems Ch. 7.9	Quiz 4 · during class
Fri, Oct 23 Homework	Homework assignment / deadline	PS 4 due PS 5 assigned · Ch. 7.6–7.9
Tue, Oct 27 Class 13	Lecture 20: The phase plane and autonomous stability Ch. 9.1–9.2	—
Thu, Oct 29 Class 14	Lecture 21: Locally linear systems Ch. 9.3	Quiz 5 · during class
Fri, Oct 30 Homework	Homework assignment / deadline	PS 5 due PS 6 assigned · Ch. 9.1–9.3
Tue, Nov 3 Class 15	Lecture 22: Competing species Ch. 9.4	—
Wed, Nov 4 Homework	Homework assignment / deadline	PS 6 due
Thu, Nov 5 Class 16	Lecture 23: Midterm review Review	Quiz 6 · during class
Fri, Nov 6 Exam	Midterm 2 6:00 p.m. · Location: TBD	—
Mon, Nov 9 Homework	Homework assignment / deadline	PS 7 assigned · Ch. 9.4–9.5
Tue, Nov 10 Class 17	Lecture 24: Predator-prey equations Ch. 9.5 Lecture 25: Laplace Transform and Initial Value Problems Ch. 6.1–6.2	—
Wed, Nov 11 Homework	Homework assignment / deadline	PS 7 due PS 8 assigned
Thu, Nov 12 Class 18	Lecture 26: Step functions Ch. 6.3	Quiz 7 · during class
Tue, Nov 17 Class 19	Lecture 27: Discontinuous forcing functions; impulse functions Ch. 6.4–6.5 Lecture 28: The convolution integral Ch. 6.6	—
Wed, Nov 18 Homework	Homework assignment / deadline	PS 8 due
Fri, Nov 20 Exam	Final exam 6:30 p.m. · Location: TBD	—

Homework and quiz dates

Section 1 problem sets and Thursday quizzes
Problem set	Assigned	Due	Textbook scope	Quiz
PS 1	Fri, Sep 18	Fri, Sep 25	Ch. 1.1–2.1	Thu, Sep 24
PS 2	Fri, Sep 25	Fri, Oct 2	Ch. 2.2–2.5	Thu, Oct 1
PS 3	Fri, Oct 2	Fri, Oct 9	Ch. 2.6, 3.1–3.3	Thu, Oct 8
PS 4	Fri, Oct 16	Fri, Oct 23	Ch. 3.4–3.6, 7.1–7.5	Thu, Oct 22
PS 5	Fri, Oct 23	Fri, Oct 30	Ch. 7.6–7.9	Thu, Oct 29
PS 6	Fri, Oct 30	Wed, Nov 4	Ch. 9.1–9.3	Thu, Nov 5
PS 7	Mon, Nov 9	Wed, Nov 11	Ch. 9.4–9.5	Thu, Nov 12
PS 8	Wed, Nov 11	Wed, Nov 18	See Canvas assignment	—

Section 1 exams

Midterm 1: Monday, October 5, 2026, 6:00 p.m. · Location: TBD
Midterm 2: Friday, November 6, 2026, 6:00 p.m. · Location: TBD
Final exam: Friday, November 20, 2026, 6:30 p.m. · Location: TBD