## Open Source for the first time

This semester, I have switched from Zill's book to an open source book.  I liked Zill - but it cost students over \$200.  Since I teach at a community college where the class itself is only about \$400, having a book half the cost of the course seemed excessive.

The book I am using is Lebl's book, available at http://www.jirka.org/diffyqs/.  I am also supplementing with Schaum's Outline of Differential Equations (http://www.amazon.com/Schaums-Outline-Differential-Equations-Outlines/dp/0071824855).  It's an inexpensive book, and has a lot of good examples and homework exercises.

There is  lot less theory in the Lebl book, so I was hoping to include more modeling activities in class than I have in the past.  And I am hoping that by posting this blog, it keeps me on target to add more modeling instead of falling back to my old notes.

I started the semester as I have the last two semesters -- with the m&m modeling with and without immigration (See 1-1-T-MandMDeathAndImmigration here on this site).  I use MATLAB (a program that most of our 4 year transfer universities use) to solve the equation since on day one, since we can't solve diff eqs yet.

The m&m modeling went very well -- and one student started asking about what happens when you have a more realistic model with a maximum population value.  This led me to include (for the first time) logistic equations when introducing slope fields.  I use dfield (at http://math.rice.edu/~dfield/dfpp.html) to generate the slope fields.   I don't think a student would have thought about population limits without starting with a real example of modeling.

By Day 4, I was ready to discuss separation of variables.  I looked through the Simiode site and found 1-16-T-DogDrugs.  It deals with the half life of medication and how much medication should be given to a dog after 2 hours to make sure the levels were at the original level.  Students initially struggled, just staring at the sheet, but one by one the class came up with pieces to be able to solve the problem.  I warned them that modeling will make them think more, but one student said, "But it's also easier because it's REAL!"

I think this is going to be a successful semester!

### Comments on this entry

1. Hi,

We welcome your Blog and we are happy (for your students) in your rationale and choices of texts and use of SIMIODE materials. Please keep "your public" informed as to how things go for you and your students in this Blog. Thank you.

Brian Winkel, Director SIMIODE

Replying to Brian Winkel

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