Math 218D-1 Spring 2026
Welcome
Welcome to Math 218D! I will post almost all course materials on this page. Please check back for information about homework assignments, exams, and additional resources. You should probably read the syllabus.
Jump to Week: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Instructors
Joe Rabinoff
jdr@math.duke.eduMath & Physics 243
Office Hours:
| M | 11am | –1pm | Math & Physics 243 |
| W | 11am | –noon | Math & Physics 243 |
Emma Bao
Undergraduate TAemma.bao@duke.edu
Office Hours:
| Tu | 7 | –9pm | Math & Physics 274J |
| W | 7 | –9pm | Math & Physics 274J |
Classes
| Lecture | Instructor | Location | Time |
|---|---|---|---|
| 218D-1 (001) | Joe Rabinoff | Math & Physics 128 | TTh 10:05–11:20am |
| 218D-1 (002) | Ruilin Shi | Math & Physics 130 | TTh 3:05–4:20pm |
| Problem Session | Instructor | Location | Time |
| 218D-1 (01D) | Soham Karwa | Math & Physics 150 | F 8:30–9:45am |
| 218D-1 (02D) | Soham Karwa | Allen 326 | F 10:05–11:20am |
| 218D-1 (03D) | Junekey Jeon | Allen 326 | F 11:45am–1:00pm |
| 218D-1 (04D) | Junekey Jeon | Gray 228 | F 3:05–4:20pm |
Resources
Rabinoff's Reliable Row Reducer
For practicing row reduction when you're allergic to fractions.
Interactive Linear Algebra
A complement to Strang's book written by Joe.
Textbook
Strang, Introduction to Linear Algebra
The official text for the course is Introduction to Linear Algebra (6th Ed) by Gilbert Strang, Wellesley–Cambridge Press/SIAM (2016). However, we will follow Strang only loosely. Another good reference is the online text Interactive Linear Algebra, by Dan Margalit and Joe Rabinoff.Help
Office Hours
Your first stop for help should be office hours! Joe, Ruilin, Soham, Junekey, and Emma will be holding plenty (times listed above), and you should not hesitate to show up with questions and chat with the other students there. If you can't make the scheduled office hours, send us an email and we'll set up a meeting.Ed Discussion
Ask questions on Ed Discussion. Your instructors and fellow students are happy to post answers for everyone to see, and usually do so much more quickly than someone can respond to an email message.
Help Rooms
The Math Department operates several Help Rooms to provide assistance to students in lower-level courses. Students are invited to drop by the Help Rooms whenever they are open. No appointment is necessary. Please check the MVLA + Probability HR Schedule to find the times dedicated to Math 218D-1.The Academic Resource Center
The Academic Resource Center (ARC) offers free services to all students during their undergraduate careers at Duke. Services include Learning Consultations, Peer Tutoring, Learning Communities, ADHD/LD Coaching, Outreach Workshops, GRE/MCAT Prep, Study Connect, and more. Because learning is a process unique to every individual, we work with each student to discover and develop their own academic strategy for success at Duke. Contact the ARC to schedule an appointment. Undergraduates in any year, studying any discipline can benefit!Schedule
| Topic and Section | Materials | Homework | |||||
|---|---|---|---|---|---|---|---|
| Week 1: 1/5 | Introduction | Joe's Notes Demo: Best fit ellipse Demo: Rabbit population Demo: A Plane Demo: Two Planes |
Homework #1 Due 1/14 11:59pm Note: HW#1 only covers the recorded lecture |
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| Vectors and Matrices (Ch. 1, 2.4, 2.7) | Joe's Notes Recorded: Watch on WarpWire (on Canvas) before the second lecture. |
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| Problem Session | |||||||
| Week 2: 1/12 | Gauss–Jordan Elimination (2.2) | Joe's Notes Gauss–Jordan Slideshow Rabinoff's Reliable Row Reducer |
Homework #2 Due 1/21 11:59pm |
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| Parametric Form, Inverses (2.5) | Joe's Notes Demo: Parameterized Line Demo: Parameterized Plane Further Reading: Computational complexity of matrix multiplication |
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| Problem Session | |||||||
| Week 3: 1/19 | LU Decomposition (2.3, 2.6) | Homework #3 Due 1/28 11:59pm |
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| Spans (2.2, 2.3) | |||||||
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| Week 4: 1/26 | Subspaces (3.1, 3.2) | Homework #4 Due 2/4 11:59pm |
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| Linear Independence and Basis (3.4, 3.5) | |||||||
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| Week 5: 2/2 | Fundamental Subspaces (3.4, 3.5) | Homework #5 Due 2/11 11:59pm |
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| Orthogonal Complements (3.5, 4.1) | |||||||
| Problem Session | |||||||
| Week 6: 2/9 | Orthogonal Projections (4.2) | Homework #6 Due 2/18 11:59pm |
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| Projection Matrices (4.2) | |||||||
| Friday, 2/13: MIDTERM 1 | |||||||
| Week 7: 2/16 | Least Squares (4.3) | Homework #7 Due 2/25 11:59pm |
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| Gram–Schmidt and QR (4.4) | |||||||
| Problem Session | |||||||
| Week 8: 2/23 | Determinants I (5.1, 5.3) | Homework #8 Due 3/6 6:59pm |
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| Determinants II (5.2) | |||||||
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| Week 9: 3/2 | Eigenvalues and Eigenvectors (6.1) | Homework #9 Due 3/18 11:59pm |
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| Diagonalization: Vector Form (6.2) | |||||||
| Problem Session | |||||||
| SPRING BREAK | |||||||
| Week 10: 3/16 | Diagonalization: Geometry (6.2) | Homework #10 Due 3/25 11:59pm |
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| Complex Numbers; Euler's Formula (9.1) | Joe's Notes Recorded: Watch on WarpWire (on Canvas) before the next lecture. |
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| AM/GM and Diagonalizability (6.2) | |||||||
| Problem Session | |||||||
| Week 11: 3/23 | Stochastic Processes and PageRank | Homework #11 Due 4/1 11:59pm |
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| Spectral Theorem (6.4) | |||||||
| Friday, 3/27: MIDTERM 2 | |||||||
| Week 12: 3/30 | LDLT; Quadratic Forms (2.7, 6.5) | Homework #12 Due 4/8 11:59pm |
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| Quadratic Optimization (6.5) | |||||||
| Problem Session | |||||||
| Week 13: 4/6 | SVD: Outer Product Form (7.1, 7.2) | Homework #13 Due 4/15 11:59pm |
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| SVD: Matrix Form (7.3) | |||||||
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| Week 14: 4/13 | PCA I (7.3, 7.4) | Homework #14 Due 4/22 11:59pm |
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| PCA II (7.3) | |||||||
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| Week 15: 4/20 | Final Exam Review | ||||||
Final exams:
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