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 TR10:3011:45am NLLC141
Course Information
 Instructor:
 Eric Olson
 email:
 ejolson at unr edu
 Please put the number 285 in the subject line.
 Office:
 Tuesday and Thursday 12 noon DMS 238 and by appointment.
 Homepage:
 http://fractal.math.unr.edu/~ejolson/28519/
 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
 Use qualitative methods to assess the behavior of solutions without solving an equation.
 Demonstrate understanding of some of different techniques for solving first and higher order homogeneous and nonhomogeneous equations: e.g. the integrating factor method, separable variables, the Laplace transform.
 Solve systems of differential equations with constant coefficients.
Announcements
[14May2019] Final Exam
The final exam will be held on Tuesday, May 14 from 9:50 to 11:50am
in NLLC 141
[08May2019] 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.
[03May2019] Answer Key for Exam 1
There is now an answer key available
for Exam 1 to help you prepare for the final exam.
[02May2019] 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.
[02May2019] 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.
[01May2019] 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.
[30Apr2019] 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.
[02Apr2019] 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.
[28Mar2019] Extra Credit 1
The following extra credit assignment from Chapter 2.6 will be due
after Spring Break on March 28.
 Exercises 2.6: Problems 2, 4, 8, 12, 13
[02Mar2019] Quiz 1 Answer Key
I have created an answer key
for Quiz 1. Please check WebCampus to verify that
your grade was recorded correctly.
[18Jan2019] 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.
Calendar
 Thursday February 21, Quiz 1
 Thursday March 28, Extra Credit 1
 Tuesday April 2, Quiz 2
 Tuesday May 2, Exam 1
 Tuesday May 14, Final (times 9:50 to 11:50am)
Homework
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 www.webassign.net 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.
Grading
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
videotaping 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