2019 Spring - MAT 2680 - Reitz

"...how it differs from the rocks"

Page 2 of 4

How to enter ‘ (prime) in WeBWorK on your iPhone

By default, the iPhone automatically converts straight quotes like this:  ‘
into smart quotes, like this ` .  You need to turn this functionality off in order to enter the prime (straight quote) symbol in WeBWorK.  The short version is:

To turn smart punctuation off, all you have to do is go to Settings > General > Keyboard, and then turn off the “Smart Punctuation” toggle.

More detailed instructions can be found here:



Course Calendar updates

Hi everyone,

Due to a number of factors (we one day behind the syllabus, Spring Break and Exam 3 timing, etc), I am making some minor changes to the class calendar – rearranging topics over the next few lectures.  The remaining material in Chapter 5 and Chapter 6 will be put off for a week or so, and tomorrow we will dive into Chapter 7 – Power Series (we’ll spend the next week or so working on this chapter).  See the most current schedule here.  Let me know if you have any questions.

Prof. Reitz




WeBWorK 9: Tips for guessing solutions to nonhomogeneous equations

Hi everyone,

As you work through WeBWorK #9, you may run into a few instances where it is not obvious what guess to make for the particular solution to the nonhomogeneous equation.  Here are two tips that might help:


What if the right side has both an exponential and a trig function?

If the right side of your differential equation has form similar to:  e^{ax} \cos(bx)

then your guess should have the form:  Ae^{ax} \sin(bx) + Be^{ax} \cos(bx)


What if the right side is a solution to the complementary equation (where the complementary equation has a repeated root)?

If your initial guess:  Ae^{ax} is a solution to the complementary equation, we adjust it by multiplying by x: Axe^{ax}.

If Axe^{ax} is *also* a solution to the complementary equation (due to a repeated root), adjust it by multiplying by x again:  Ax^2e^{ax}.


Let me know if you run into other weird things.  Questions are natural, and welcome!

Prof. Reitz

Assignments Week 9

WeBWorK: Assignment  9-Nonhomogeneous  due Tuesday, 4/2, at midnight.
NOTE: Because of our exam on 4/2,  assignment 10-Trench-ReductionOfOrder will be due the following Tuesday, 4/9.

OpenLab:  OpenLab #2: Numerical Methods PROJECT is due Thursday, 4/4, by the start of class.


« Older posts Newer posts »