Welcome to Differential Equations! For course info and policies, please see the syllabus. For grades, log into Moodle. If you need help or have questions, please contact Prof. Wright; office hours are Mon. 1:15–1:45 & 3–3:30, Wed. 9–10, Thurs. 10–11 & 1–2, Fri. 1:15–1:45 & 3–3:30, or by appointment in RMS 409.
Below is a tentative outline of the course. Use the controls at right to make the page easier to view.
Unless otherwise noted, homework listed below is assigned on the day indicated and due in the homework mailbox at 4:00pm on the next class day. For example, homework assigned on a Wednesday is due at 4:00pm Friday.
Day  Topic  Homework Assigned 

Friday Sep. 9  Modeling with differential equations; 230A notes; 230B notes 
Do the following:

Day  Topic  Homework Assigned  Labs 

Monday Sep. 12  Separation of variables; 230A notes; 230B notes  Read §1.2, do #1, 3, 5, 8, 15, 17, 25, 28  
Wednesday Sep. 14  Slope fields; 230A notes; 230B notes; mixing problem  Read §1.3, do #1, 3, 8, 11, 13, 14, 16, 17 Note: You do not need to use HPGSolver; instead, you may use Mathematica, Desmos, GeoGebra, or other technology.  
Friday Sep. 16  Meet in Tomson 188 computer lab Euler's method  Read §1.4, do #1, 3, 5, 6, 11; Watch the video Existence and Uniqueness before next class.  Lab 1 assigned; due Sept. 28 
Day  Topic  Homework Assigned 

Monday Sep. 19  Existence and uniqueness; 230A notes; 230B notes; solutions to practice problems  Read §1.5, do #2, 3, 5–8, 9ab, 11, 13 
Wednesday Sep. 21  Phase line; 230A notes; 230B notes  Read §1.6, do #1, 4, 7, 10, 13, 16, 19, 31, 32, 33 
Friday Sep. 23  Bifurcations; 230A notes; 230B notes  Read §1.7, do #4, 8, 9, 11, 12, 13, 16 
Day  Topic  Homework Assigned  Labs 

Monday Sep. 26  Linear differential equations; 230A notes; 230B notes  Read §1.8; Watch the video The Integrating Factor Method before next class.  Lab 1 due Wednesday 
Wednesday Sep. 28  Integrating factor method; 230A notes; 230B notes; solutions to practice problems  Do §1.8 exercises #1, 4, 5, 8, 10, 17, 19, 23; Read §1.9, do #1, 4, 5, 15, 19, 23  Lab 1 due today 
Friday Sep. 30  Systems of linear equations; 230A notes; 230B notes; LotkaVolterra plotter  Read §2.1; Do #1–4, 7a, 8ab, 15 
Day  Topic  Homework Assigned  Labs 

Monday Oct. 3  Geometry of systems; 230A notes; 230B notes  Do §2.1 exercises #20, 21, 22; Read §2.2, do #5, 9, 11, 14, 21  Lab 2 assigned; due Oct. 21 
Wednesday Oct. 5  Damped harmonic oscillation; 230A notes; 230B notes  Read §2.3, do #1, 2, 5, 6, 7  
Friday Oct. 7  Additional analytic methods; 230A notes; 230B notes  Read §2.4, do #1, 2, 5, 6, 7, 10, 13 
Day  Topic  Homework Assigned 

Monday Oct. 10  More about systems; 230A notes; 230B notes  Study for the exam 
Wednesday Oct. 12 
Exam 1
 
Friday Oct. 14  Linearity principle for systems; 230A notes; 230B notes  Read §3.1, do #5, 9, 15, 16, 24, 27, 29 
Day  Topic  Homework Assigned  Labs 

Monday Oct. 17  Fall Break — no class!  
Wednesday Oct. 19  Straightline solutions; 230A notes; 230B notes  Read §3.2  Lab 2 due Friday 
Friday Oct. 21  Linear systems with real eigenvalues; 230A notes; 230B notes  Do §3.2 exercises 1, 2, 4, 5, 11, 12, 21; Read §3.3, do #1, 2, 9, 10, 13  Lab 2 due today 
Day  Topic  Homework Assigned  Labs 

Monday Oct. 24  Linear systems with complex eigenvalues; 230A notes; 230B notes; Bonus: video on e^{iπ}  Read §3.4, do #1, 2, 9, 10, 11  
Wednesday Oct. 26  Linear systems with complex or repeated eigenvalues; 230A notes; 230B notes  Do §3.4 exercises #6, 12, 15, 16, 23; Read §3.5, do #1, 9, 10  Lab 3 assigned; due Nov. 11 
Friday Oct. 28  Linear systems with repeated or zero eigenvalues; 230A notes; 230B notes  Do §3.5 exercises 3, 7, 11, 17, 18, 21, 22 
Day  Topic  Homework Assigned 

Monday Oct. 31  Linear system summary and tracedeterminant plane; 230A notes; 230B notes  Read §3.7 
Wednesday Nov. 2  Tracedeterminant plane; Secondorder linear equations; 230A notes; 230B notes  Do §3.7 exercises #1, 2, 3, 5, 11, 12; Read §3.6, do #1, 2, 6, 7, 10 For these problems, a "brief essay" can be a sentence or two. 
Friday Nov. 4  Secondorder linear equations; Forced harmonic oscillation; 230A notes; 230B notes  Do §3.6 exercises #13, 16, 21, 24, 33; Read §4.1 
Day  Topic  Homework Assigned  Labs 

Monday Nov. 7  Forced harmonic oscillation; 230A notes; 230B notes  Reread §4.1, do #1, 5, 9, 13, 16, 22, 26, 33, 37  
Wednesday Nov. 9  Sinusoidal forcing; 230A notes; 230B notes  Read §4.2  Lab 3 due Friday 
Friday Nov. 11  Undamped forcing and resonance; 230A notes; 230B notes; Desmos: forced oscillator, undamped forced oscillator  Do §4.2 exercises #1–4, 11, 17, 19; Read §4.3, do #5  Lab 3 due today 
Day  Topic  Homework Assigned  Labs 

Monday Nov. 14  Forced oscillation and resonance; 230A notes; 230B notes; Desmos: Undamped forced oscillator  Do §4.3, #15, 17, 21 (not to be collected); Study for the exam  
Wednesday Nov. 16 
Exam 2
 
Friday Nov. 18  Nonlinear systems: equilibrium point analysis; 230A notes; 230B notes  Read §5.1, do #1, 4, 5, 9ab, 18, 21  Lab 4 assigned; due Dec. 9 
Day  Topic  Homework Assigned 

Monday Nov. 21  Qualitative analysis of nonlinear systems; 230A notes; 230B notes  Read §5.2, do #3, 7, 8, 17, 19, 21 
Wednesday Nov. 23  Thanksgiving Break — no class!  
Friday Nov. 25  Thanksgiving Break — no class! 
Day  Topic  Homework Assigned 

Monday Nov. 28  Qualitative analysis of nonlinear systems; 230A notes; 230B notes  Do §5.2, #9, 16, 18; Read §5.3, do #1, 2, 3 In problems #1–3, you may ignore "saddle connections" for now. 
Wednesday Nov. 30  Hamiltonian systems; 230A notes; 230B notes  Do §5.3 exercises 9, 10, 11, 12, 14, 15, 18 
Friday Dec. 2  The Laplace transform; 230A notes; 230B notes  Read §6.1, do #1, 2, 6–10, 15, 16 
Day  Topic  Homework Assigned  Labs 

Monday Dec. 5  Laplace transform for discontinuous functions; 230A notes; 230B notes  Read §6.2, do #1, 2, 3, 5, 7, 9, 11  
Wednesday Dec. 7  Laplace transform for secondorder equations; 230A notes; 230B notes  Read §6.3  Lab 4 due Friday 
Friday Dec. 9  Delta functions and impulse forcing; 230A notes; 230B notes  Do §6.3 exercises #5, 11, 15, 27, 30; Read §6.4, do #2, 3, 5, 7  Lab 4 due today 
Day  Topic 

Monday Dec. 12 
Review for final exam. Solutions to inclass problems. Final Exam Information:

Friday Dec. 16  Final exam for Math 230B 2:00 – 4:00pm 
Day  Topic 

Monday Dec. 19  Final exam for Math 230A 9:00 – 11:00am 