# MA226 Diff Eqns Spring 2017

### Announcements

- EXTRA OH: Eric MCS B46B Thursday 2:30-4:30 pm, Monday 5-6pm. Come pick up your projects!
- Final Exam info
- School of Communications room 101 on Tuesday May 9 from 9am-11am.
- the material from the projects will not be on the exam. knowing the trace-determinant plane is helpful but not necessary.
- expect a question on bifurcations, mixing, and euler's method. a question may be a full question or a short answer, or a true false, or a multiple choice.
- you will get a photocopy of page 626 to use for your final exam.
- solutions to Devaney's 2011 final and 2015 exam 3 ARE POSTED BELOW.
- so are the notes from Angus' discussions in the last week - this is the review style one.

- Project 2 info
- Come get your projects during OH today! They will also be at the final exam.

- Project 1 info
- You may qualify for a regrade on your project. If you lost points for not specifying you were in a subset
**OR for using the axes as eigenvectors**, you should bring your project to my or Angus' OH

- You may qualify for a regrade on your project. If you lost points for not specifying you were in a subset

### Homework

- Chapter 6 Laplace Transforms
- 6.1 - 1-3, 7-14, 15-23 odd, 25
- 6.2 - 1, 3, 4-13, 15, 17
- 6.3 - 11-18, 27-34, [OPTIONAL: 19-26]
- 6.4 - 2-5, 6, 7.

For #6, use the section from "Impulse Forcing of a Damped Harm. Osc." on p604 as a model.

- Chapter 5 Nonlinear Systems
- 5.1 - 1, 7-15 odd, 21-25 odd, 26-29
- 5.2 - 1, 4, 5-13 odd, 15, 19

- Chapter 4 Forcing and Resonance
- 4.1 - 3-17 odd, 21-27 odd, 33-37 odd
- 4.2 - 1-9 odd, 11-15, 18-20
- 4.3 - 1-21 odd, 22, 24

- Chapter 3 Linear Systems
- 3.1 - 5-8, 16,17,25,27
- 3.2 - 1-13 odd, 19-24
- 3.3 - 1-11 odd, 13-16, 21
- 3.4 - 1, 2, 3-13 odd, 19, 20
- 3.5 - 1-8, 11, 13, 17-22
- 3.6 - 13-27 odd, 29, 36

- Chapter 2 First Order Systems
- 2.1 - 1,2,8,9-14,18
- 2.2 - 8,11-14,16,18,21,23,25
- 2.3 - 1-7
- 2.4 - 1-13 odd
- 2.5 - 1,2

Use technology! - 2.6 - 3,4,6,7

- Chapter 1 First Order Differential Equations
- 1.1 - 1-6, 11-14, 17, 18
- 1.2 - 1, 7, 10, 14, 15, 17, 19, 20, 22, 24, 33, 35, 37, 41, 42
- 1.3 - 1a, 3a, 5a, 13, 14, 16
- 1.4 - 1, 2, 5, 6.

Use technology for 1,2. Try 5,6 by hand (but with a calculator). - 1.5 - 1-8, 13-16
- 1.6 - 1, 2, 4, 5, 7, 13, 14, 16, 17, 19, 30, 31, 32, 34, 35, 36.

For #13-21, some of the detail in the graphs in the back of the book is unrealistic to sketch by hand. - 1.7 - 1-9, 13, 19, 20
- 1.8 - 1,3,4,5,7,9,11,17,19,20,21,23,29,31
- 1.9 - 1-13 odd, 19,21,23, 24-27

### Quick reference

- Text: Differential Equations 4E by Blanchard, Devaney, Hall
- Software: Cengage DETools no install .jar file
- Class meets: TR 9:30-10:45 @ CGS 511
- Office hours: Tues 11:15-12:15, Thurs 12:30-1:30 @ MCS B46B
- Email: changer@bu.edu
- Teaching Fellow: Angus McAndrew at angusmca@bu.edu
- Office hours: Mon 11:15-12:15, Tues 12:30-1:30 @ MCS B45
- Tutoring room hour: Tues 11:15-12:15 @ MCS B24

### Significant dates

- May 9: Final Exam. School of Communications room 101 from 9am-11am.

### Discussions

- Tues 2:00 - 2:50 pm PSY B47
- Tues 3:35 - 4:25 pm PRB 150
- Wed 9:05 - 9:55 am CAS 424
- Wed 10:10 - 11:00 am MCS B23
- Wed 4:40 - 5:30 pm MCS B23

### Documents

- Notes from Angus' review discussion
- Exercise 6.2.17 (and #16 as well)
- Exercise 5.2.15
- Exercise 5.1.26
- Exercise 5.1.25
- 5.2 example nullclines that are not lines
- Exercise 4.3.15
- Exercise 4.2.15b
- Project 2 Due Apr 27
- Project 1
- Syllabus
- Schedule
**updated since 3/14 snow day. hit refresh.** - Exercise 1.9.25
- Exercise 1.9.26A disregard part b
- Exercise 1.9.26B part b

### Quiz and Exam solutions

- Devaney's final 2011 don't worry about #6, and #7 is covered in exam3
- Devaney's exam3 Fall2015 the answer to #1 should have a coefficient of 1, not 4/3
- quiz9
- quiz8 2 sets of solutions, depending on method
- quiz7 page1
- quiz7 page2
- exam2
- quiz6
- Devaney's exam2 Fall2015 #5.3 answer is incorrect!
- quiz5
- quiz4
- exam1
- quiz3
- quiz2
- quiz1