MATH 23:  Differential Equations


Dr. S. Pauls


Text:  Elementary Differential Equations and Boundary Value Problems, 7th edition.  Boyce and DiPrima


Course Details


MWF 11:15am-12:20pm, Bradley 103

x-hour Tuesday 12:00pm – 12:50pm, Bradley 103


Instructor Information


Office:  404 Bradley

Phone: 646-1047


Office Hours:  Monday 3-4pm, Tues 2-3pm, Friday 10-11am





In this course we will cover some of the techniques used to solve differential equations, building on the techniques covered in math 5, 8, and 13.  These include but are not limited to separation of variables, constant coefficient methods, the method of undetermined coefficients, variation of parameters, applications of linear algebraic methods to systems of equations, series solutions, Fourier series solutions and transform methods.  The objective of mastering these techniques is to apply them to differential equations which model physical or “real world” situations.  Although we will see numerous applications of this type throughout the semester, the main goal of the course is to apply the techniques to three of the most important differential equations in physics:  the Laplace equation, the heat equation and the wave equation. 


Course Structure and Expectations


Exams:  This course will have one take home midterm exam handed out February 1, 2002 and due February 7, 2002.  There will also be a final exam, scheduled by registrar.  As the registrar has yet to schedule final exams, no student should leave the Hanover area before the 14th of March.   No exceptions or arrangements will be made for students who do not make their travel arrangements appropriately. 


Reading Assignments:  There will be regular reading assignments for the course.  You are expected to read the relevant sections before coming to the class in which we discuss this material.  


Homework:  There will be regular homework assignments.  Usually, there will be problems assigned at the end on one class period which will be due at the beginning of the next class. 


Quizzes:  I reserve the right to give an unspecified number of quizzes throughout the term.  These quizzes may or may not be announced.  Unannounced quizzes tend to correlate inversely to the amount of assigned reading the class is completing. 




The course grade breaks down roughly as follows:


Midterm:  100 points

Final Exam:  150 points

Homework:  100 points

Quizzes/Misc:  50 points


Total:   400 points


Depending on the number of quizzes, the contribution of quizzes to the final grade may be raised or lowered.  If a change occurs, I will explain the change completely in class.


Rough Syllabus


Week 1:  First and second order linear ODEs, review of separable equations, constant coeef methods, modeling of physical systems, etc.  (Chapter 2 and the beginning of chapter 3)


Week 2: End of chapter three and chapter 4, including method of undetermined coefficients and variation of parameters. Applications to physical systems associated to vibrations.


Week 3:  Chapter 5, power series and series solutions.  Be prepared – review series and power series!


Week 4: More series solutions and beginning of systems of equations (chapter 7)


Week 5:  Review of necessary linear algebra, techniques for homogeneous linear system with constant coefficients.  (More of chapter 7)


Week 6:  More complicated systems of linear equations, phase planes (parts of chapters 9 and 10)


Week 7:  Fourier series, introduction to partial differential equations and separation of variables (Chapter 10)


Week 8:  Applications of separation of variables to the Heat and Wave equations.


Week 9:  More wave equation and applications to Laplace’s equation. 


Week 10:  Supplemental topics and/or catch-up.