Final Grades are submitted

Hi everyone,

I’ve submitted grades through CUNYFirst, and posted a detailed breakdown on the GRADES page (email me if you don’t remember the page password).

Best of luck to all, and enjoy your summer.

Take care,
Prof. Reitz

Exam #3 Grades are posted

You can find them on the “Grades” page (if you forgot the password, email me).

Best of luck with your studying,
Prof. Reitz

OpenLab #4: Advice for the future

(Due Thursday, 5/22/14, at the start of class).  Imagine that you are invited to speak on the first day of MAT 2680, to give advice to entering students.  Write at least three sentences responding to one or two of the following, describing what you would tell them.

  1. What do you wish that you had been told at the start of this class, to help you succeed?
  2. Choose one topic in the course that is especially challenging. Identify it, and give advice to students trying to master that topic.
  3. What is the most important prior knowledge (not taught in the class) that you need in order to succeed?  Why is it important?

Extra Credit.  Respond to someone else’s comment.  Do you agree? disagree? Have anything to add?

Final Exam Review Sheet is posted

UPDATE 5/17/14:  Corrected ALL answers to problem #17 (numerical methods).

Posted on the “Exam Reviews” page. ¬†As always, let me know if you find errors or have questions.


Prof. Reitz

Exam 3 Review Sheet is posted

UPDATE 5/10/2014: Correction to answer #3 — it should be “-” not “+”. ¬†(This also affects the value y(1.2)). ¬†

UPDATE 5/8/2014: Runge-Kutta data & formulas have been added.

UPDATE 5/6/2014, 1:20pm: Correction to answer #4d ¬†—¬†

4d:  49e^{16t}+cos{7t}

It can be found on the “Exam Reviews” page.

NOTE: some of the information about the Runge-Kutta method is missing – this will be added within the next few days.

Best of luck,
Prof. Reitz

Special Offer – 1 week only – WeBWorK RE-OPENED

Hi everyone,

All of the past WeBWorK assignments have been re-opened – this is your chance to make up for work you might have missed earlier in the semester.

They will all be closed again next Saturday night, May 10th, at midnight.

Why now? ¬†Well, you still don’t have your Exam 3 review sheet, so this gives you something to work on in the meantime (the Review Sheet will be posted later this weekend).

Why only one week? ¬†While I like the idea of giving you a chance to make up your incomplete assignments, I don’t want this to be a serious distraction as we approach the final. ¬†Also, it’s a special offer – no complaints!

Best of luck to you all,

Prof. Reitz


MAT3880: Partial Differential Equations through Mathematical Models in Biology

Hi everyone,
If you’re interested in pursuing differential equations further, I highly recommend this course being taught in the fall.
Prof. Reitz
Attention Differential Equations Students!
One of the most fascinating and important areas of active mathematical research is Mathematical Biology—the art and science of studying life through mathematics and the mathematics of life.¬† MAT3880: Partial Differential Equations through Mathematical Models in Biology¬†covers important current topics in this important field.¬† The course provides a solid foundation in the concepts and methods of partial differential equations within the context of biology.¬†
The class meets MW 2:00-3:15pm.

Office hours today (almost) normal

Hi everyone,

I am in my office from 11am-1pm today, with the exception of a brief meeting from 11:30-12:00.

Prof. Reitz

Office Hours, Thursday 4/10/14

Hi everyone,

Today I will be:

1.  In my office from 11:00 Р11:30

2. If no-one shows up, I will be attending an event from 11:30-12:30 – HOWEVER, if you send me an email to: jonasreitz (at), I will get it on my phone and come back to my office to meet with you.

Prof. Reitz

OpenLab #3: Flipping the class – Inverse Laplace Transforms and Partial Fraction Decomposition

One of the strongest results from our OpenLab #2 Survey was a request for more examples & problems in class.  As you know, our class time is quite limited Рso to take maximum advantage of the time we have, we are going to try an experiment.  This OpenLab assignment, to be completed over the Spring Break, will ask you to get a head start on upcoming material by watching a few videos on the material.  This will hopefully free up some class time for more examples & problems.

Assignment¬†(Due Thursday, April 24, at start of class). ¬†Watch the videos below. ¬†You MUST watch the videos marked “required”. ¬†You CAN also watch the videos marked “optional,” – if you have any questions about today’s lecture, or if you need a reminder of how to do Partial Fractions, you should watch the appropriate videos here. ¬†Test your understanding by completing this problem:

Example. Find the Inverse Laplace Transform of :  \frac{4 s^2+27}{s (s^2+9)}

Partial fraction decomposition: \frac{4 s^2+27}{s (s^2+9)} = \frac{s}{s^2+9}+\frac{3}{s}
Inverse Laplace Transform:  \cos (3t) + 3

Then respond to the following prompts.

  1. What is one thing you learned from (any) one of the videos? What is one thing that you didn’t understand, or found confusing?
  2. Any questions about the example above?
  3. Any comment on this assignment? (helpful, confusing, useful, irritating, etc – what did you think of it?)

Extra Credit.¬† You can earn extra credit by making up a problem and posting it here (do NOT post the solution yourself – let other people solve it!), or by giving a solution to someone else’s posted problem. ¬†Simple problems are fine – it can be much simpler than my example above. ¬†It should be one of the following types of problems:

  1. Finding the Laplace Transform (like we did today)
  2. Finding the Inverse Laplace Transform, or
  3. Partial Fractions

How do I type math formulas on the OpenLab?¬†You can always type mathematical formulas just as you would type them into a TI-83 calculator, for example “sin(2t)+e^x”. ¬†But if you want them to look pretty (like this: ¬†\sin (2t) + e^x) you can do that too – here’s a guide (see the section “Typing math on the OpenLab” about halfway down the page).



  1. Overview: How do we use the Laplace Transform to solve differential equations?  2 min.
  2. The Inverse Laplace Transform.  6 min.
    NOTE: The first minute and a half is a more abstract discussion Рfollow it as best you can.  BUT hold on for the example, which starts at 1:25.
  3. (This is not required, but if you like these videos, he has a whole playlist of videos on the Laplace Transform here: )


  1. Finding the Laplace Transform of a Function:  3 min.  This is a useful example of what we did in class today Рit will also help you with WeBWorK 14.
  2. Partial Fraction Decomposition Рa basic example.  This is a good basic example. 
  3. Partial Fraction Decomposition Рanother example. This is a slightly longer example, and it includes a good explanation of how to set up your partial fractions for different kinds of factors in the denominator.