Mathematics 285

Spring 2018 University of Nevada Reno

285 DIFFEREN EQUATIONS (3) 3 credits

Instructor   Course Section                    Time                Room
Eric Olson   1004 Math 285 DIFFEREN EQUATIONS  TR10:30-11:45am  NLLC141

Course Information

Eric Olson
ejolson at unr edu
Please put the number 285 in the subject line.
Tuesday and Thursday 12 noon DMS 238 and by appointment.

Required Texts:
Dennis Zill, A First Course in Differential Equations with Modeling Applications, 10th or 11th Edition, Brooks Cole, 2012 or 2017.

Student Learning Outcomes

We will cover selected sections in Chapters 1 through 5, 7 and 8 of the textbook. Upon completing this course, a student shall be able to


[14-May-2019] Final Exam

The final exam will be held on Tuesday, May 14 from 9:50 to 11:50am in NLLC 141

[08-May-2019] Additional Review Problems

Note that the final exam will cover material from the entire semester. I have created a supplement of additional study problems and a corresponding answer key to help you prepare for the final exam. In addition, please carefully review all previous quizzes, exams and study guides.

[03-May-2019] Answer Key for Exam 1

There is now an answer key available for Exam 1 to help you prepare for the final exam.

[02-May-2019] Answer Key for Extra Credit

I have created an answer key for the extra credit problems. The extra credit will be graded shortly as will Exam 1. An email will be sent when the scores have been posted.

[02-May-2019] Exam 1

The first exam (third quiz) in preparation for the final exam will be given in class Thursday, May 2. I have prepared a sample exam and key to help you study. I have scanned the table of Laplace transforms that will appear attached to Exam 1 and also on the final exam.

[01-May-2019] Eigenvectors with Maple

In class we found the eigenvalues and eigenvectors of a matrix using the computer algebra system called Maple. This program is available on the computers in the UNR Math Center. For reference the worksheet which we used looked like

The interpretation of this output is that there are two eigenvectors and two eigenvalues: The eigenvalue −1 corresponds to eigenvector (−1,1) and the eigenvalue 5 corresponds to eigenvector (1/2,1).

There is another computer algebra system called Mathematica that is available through UNR Remote Desktop on campus and from home. The same calculation performed using this program looks like

Note that the eigenvalues produced by either program are the same, though in reverse order, but the programs report different eigenvectors for the eigenvalue 5. In particular, the eigenvector (1,2) found by Mathematica is double the eigenvector (1/2,1) found by Maple. This is okay because an eigenvector can be rescaled and still be an eigenvector for the same eigenvalue. In particular, either eigenvector will work equally well when solving linear systems of ordinary differential equations. Feel free to use either program to answer questions that need eigenvectors and eigenvalues on the computer homework system.

[30-Apr-2019] Exam 1 Answers

I have created an answer key to the sample exam to help you study for Exam 1 which will be given Thursday, May 2.

[02-Apr-2019] Quiz 2

The second quiz will be Tuesday, April 2. I have prepared a sample quiz to help you study. There is now an answer key to check your answers on the sample quiz.

[28-Mar-2019] Extra Credit 1

The following extra credit assignment from Chapter 2.6 will be due after Spring Break on March 28.

[02-Mar-2019] Quiz 1 Answer Key

I have created an answer key for Quiz 1. Please check WebCampus to verify that your grade was recorded correctly.

[18-Jan-2019] Academic Success Services

Your student fees cover usage of the These centers support your classroom learning and it is highly advised that you take advantage of their services. Keep in mind that seeking help outside of class is the sign of a responsible and successful student.



All homework is to be completed on Webassign. You are responsible for keeping track of all assignments and their due dates. Solving homework problems will help you to understand the key concept and to master the skills you will need to succeed in this course. You should try to work on the problems assigned for a section as soon as the material is covered. You may discuss problems with other students, but all submitted work should be your own. Go to and use the code

unr 8885 2928

You will be asked to set up a Webassign account if you do not already have one. Please use exactly the same name and email you use to register for courses at UNR.


     Quiz 1                    20 points each
     Quiz 2                    40
     Exam 1                    60 points
     Final Exam               100 points
     Homework Assignments      40 points
                              260 points total

Exams and quizzes will be interpreted according to the following
grading scale:

    Grade        Minimum Percentage
      A                 90 %
      B                 80 %
      C                 70 %
      D                 60 %

The instructor reserves the right to give +/- grades and higher grades
than shown on the scale if he believes they are warranted.

Final Exam

The final exam will be held on Tuesday, May 14 from 9:50 to 11:50am in NLLC 141.

Equal Opportunity Statement

The Mathematics Department is committed to equal opportunity in education for all students, including those with documented physical disabilities or documented learning disabilities. University policy states that it is the responsibility of students with documented disabilities to contact instructors during the first week of each semester to discuss appropriate accommodations to ensure equity in grading, classroom experiences and outside assignments.

Academic Conduct

Bring your student identification to all exams. Work independently on all exams and quizzes. Behaviors inappropriate to test taking may disturb other students and will be considered cheating. Don't talk or pass notes with other students during an exam. Don't read notes or books while taking exams given in the classroom. Homework may be discussed freely. If you are unclear as to what constitutes cheating, please consult with me.

The following is new university policy: Surreptitious or covert video-taping of class or unauthorized audio recording of class is prohibited by law and by Board of Regents policy. This class may be videotaped or audio recorded only with the written permission of the instructor. In order to accommodate students with disabilities, some students may be given permission to record class lectures and discussions. Therefore, students should understand that their comments during class may be recorded.

Last Updated: Thu Jan 24 08:54:47 PST 2019