September-December 2017: Math 215/255: Differential Equations Common Page
Instructors: Daniel Coombs, Sarafa Iyaniwura and Aaron Palmer
Math department tutoring centre is located in LSK 301/302.

Links to section web pages:
  • Section 101 (Palmer, 8am in LSK 201)
  • Sections 102+103 (Coombs, 9am in DMP310 and 1pm in LSK200)
  • Section 104 (Iyaniwura, 1pm in IKBLC 261)

  • Text: Our main reference will be the online textbook Diffy Qs by Lebl. You can download the book (for free) or order a copy (for cheap) to be sent to you from this page:
  • Clickers will be used in some sections of this course. Please confirm with your section instructor about whether you need to get a clicker (available from the bookstore).
  • Matlab/Octave. You will need one of these tools for some of the homework in this class. See below for instructions about how to get one of these programs for your personal computer. You can also/alternatively use the Math department computer labs.
  • Additional free online notes are available at the following sites:
    Paul's online notes (highly recommended) (for the last link you will need to be accessing from UBC, either directly or via VPN:
    You can also consult physical textbooks. Some favourites are Boyce and DiPrima (any recent edition) and Edwards and Penney. Boyce and DiPrima has often been used at UBC.
  • Gustafson's notes on nonlinear systems

    Important Dates:

  • First class: Sept 6th, 2017.
  • Midterm test 1: Wednesday, October 18th (in class)
  • Midterm test 2: Wednesday, November 15th (in class)
  • Final exam: December 9th, 2017 at 12pm. Locations: Section 101 (8am, Palmer) will go to HEBB 100. Sections 102 and 103 (9am and 1pm, Coombs) will go to WOOD 2. Section 104 (1pm, Sarafa) will go to ANGU 098.

    Final Exam Resources

  • Detailed list of topics for the course [PDF]
  • Laplace Transform table [PDF]
  • Previous math 215 exams. Note that different topics receive more or less emphasis in different years. See the list of topics (final page) for some more information about which questions from previous final exams are relevant.
  • UBC Math Exam Resources wiki.
  • UBC Math club.Will sell you some previous exams with solutions. Carefully note their opening hours.
  • Additional review problems with solutions.


  • The breakdown of marks between course elements will be as follows: Final exam 50%, Homework 15%, Webwork 10%, Midterms 10% each, in-class quizzes, questions and/or clickers 5%.
  • Missing a midterm or quiz normally results in a mark of 0. Exceptions may be granted in two cases: prior consent of the instructor or a medical emergency. In the latter case, the instructor must be notified within 48 hours of the missed test, and presented with a doctor's note immediately upon the student's return to UBC. No make-up midterms will be given.
  • A student must get at least 40% on the final exam to pass this course. A student who gets less than 40% on the final exam and whose grade computed by the grading scheme would be a passing grade shall receive a final grade of 48%.
  • Term marks may be scaled up or down on a classwide basis, depending on performance on the final exam. This is to ensure fairness across all sections of the course.
  • You must submit only your own work. Although you are welcome to study together and discuss the homework with other students, the work you submit (electronically or on paper) must be your own. UBC policies on cheating and plagiarism are extremely strict. If in doubt, enquire before submitting.
  • Not all homework problems will necessarily be graded.

    Written Homework

  • All homework must be stapled.
  • Homework set 1 due in class, Friday Sept 22. You will need this Matlab file: dirfield.m for this homework. Also here are some notes on basic Matlab usage: [PDF]. Tex source for problems: [tex].
  • Solutions. You will also need to run these Matlab files to get the plots: Problem 2; Problem 3; Problem 8.
  • Homework set 2 due in class, Friday Oct 6. You will need these Matlab files: EulerHW2.m; ImprEulerHW2.m for this homework. Tex source for problems: [tex].
  • Solutions.
  • Homework set 3. Part one is for practice before the first midterm. Part two (only) must be submitted in class on October 27.
  • Solutions (1).
  • Matlab script that can be edited for use in HW3 part 2: vecfield_systems.m
  • Solutions (2).
  • Homework set 4 due in class, Friday Nov 10. You may want to adjust this Matlab file when working on problem 7: two_salt_tank_mixing_w_forcing.m.
  • Solutions.
  • Homework set 5. Due in class, Friday November 24.
  • Solutions.
  • Homework set 6. This will not be collected but you should complete it as practice for the final exam.
  • Solutions (updated to correct error in solution to problem 7 parts b and c on Dec 3).


    Webwork will be due before 10pm on Mondays, starting from Monday September 18th. Please login to the course webwork page. The problems will be available 5-7 days in advance.

    Midterms and Quizzes

  • List of topics for midterm 1.
  • Spring 2017 midterm and Solutions
  • Midterm 1: Section 101; Section 102; Section 103/104
  • Midterm 1 Solutions: Section 101; Section 102; Section 103/104
  • List of topics for midterm 2.
  • Abridged 2016 midterm and Solutions.
  • 2007 midterm and Solutions.
  • 2014 midterm 2 and Solutions.
  • 2014 midterm 3 and Solutions.
  • Spring 2017 midterm 2 and Solutions
  • Midterm solutions (AM 1)
  • Midterm solutions (AM 2)
  • Midterm solutions (PM 1)
  • Midterm solutions (PM 2)

    Computer homework information

    Getting the needed software

  • Computer homework information will be given in class as needed.
  • Here are three options for obtaining software needed for the homework.
  • (1) Matlab is available from UBC IT services for UBC students to install on their own computers. You do not need any additional toolboxes for this class.
  • (2) You can install Octave. Octave is a free program that is quite similar to Matlab so that most programs are easily portable from one to the other. Installation of Octave on Windows and Linux is fairly simple (in fact if you have a recent Linux distribution, Octave might already be installed). However on Mac computers, installation has been reported to be a bit trickier. We will not help you install software on your personal computer.
  • (3) You can use the Mathematics undergrad computer labs, located in LSK 121 and LSK 310. The labs are open from 8am-6pm Monday to Friday. LSK 310 is also where the TA help will be available (either on a lab computer, or take your laptop). To use the lab computers you will need to login using a user account. Follow the instructions that will be sent to you by email (and/or ask the TAs during lab hours for assistance).

    Lab TA hours:

    For help with Matlab, TAs will be available in LSK 310 at the following times (subject to change through the semester, please check back for updated hours):
  • Wednesday: 4pm-6pm (1 TA)
  • Thursday: 2pm-4pm (1 TA) and 4pm-6pm (2 TAs)

    Matlab and Octave resources

  • UBC Math Matlab/Octave resources page.
  • Matlab is used by lots of people worldwide. The Mathworks help site is a good place to look for help, but often you will also find an answer by directly using Google or another search engine.
  • Useful notes on Matlab for novices [PDF].
    Daniel Coombs / Department of Mathematics / University of British Columbia