John D. Cook’s daily Twitter tips

One of the most prolific and interesting math bloggers and Twitters, John D. Cook (his blog is The Endeavor and he is @JohnDCook on Twitter) has been using Twitter in a very interesting way. In addition to his personal account, he has set up more than half a dozen daily Twitter messages on a variety of…

Mathematical cousins and collaboration numbers

A couple days ago Michael Lugo at God Plays Dice shared a link to a mathematical relationships search. Enter the names of two people with PhDs in mathematics and it will spit out their academic relationship. For example, my advisor, John Franks, is my academic father and my good friend and collaborator Jim Wiseman is my academic…

An Euler line geogebra applet

Lately I’ve been thinking a lot about Euler and his many contributions to mathematics. So, just for fun I decided to make a Geogeba applet showing the “Euler Line.” In 1763 Euler proved that three different centers of a triangle—the centroid, the orthocenter, and the circumcenter—are collinear. This line is called the Euler line. The centroid…

Using wikis in mathematics classes

Wikipedia describes a wiki as a website that allows the easy creation and editing of any number of interlinked web pages… [Wikis] are often used to create collaborative websites, to power community websites, for personal note taking, in corporate intranets, and in knowledge management systems. I have used wikis in three of my classes: two…

Posting items to my blog using wplatex

This blog post is aimed at other mathematicians who write on WordPress blogs. I’m writing this blog post completely in TexShop on my Mac! Recently I discovered that Eric Finster at Curious Reasoning wrote a Python script called wplatex that converts LaTeX documents to HTML that is WordPress compatible. Then it posts the files directly…

Three applets illustrating parametric curves

In my multivariable calculus we’re talking about parametric curves. I’m using this applet for displaying parametric curves. You can use predefined curves or enter your own. Although the applet is on my web page, it was created by Marc Renault, a friend who teaches down the road at Shippensburg University. I only tweaked it slightly when…

Three applets for linear algebra or multivariable calculus

This semester I’m teaching two sections of Calculus III (multivariable calculus) and I happen to be teaching the first four weeks of Linear Algebra. The first couple weeks of both courses cover properties of vectors in Rn. (Of course, just to confuse the instructor and the students who happen to be in both classes, the…

Division by Zero listed as one of 50 Best Blogs for Education Leaders

This morning I was pleased to discover that my blog appears on OnlineUniversities.com‘s blog in their list of the 50 Best Blogs for Education Leaders; it was one of the five blogs listed in the Subject Specific category. What a nice surprise. I’m very honored for the recognition! This is the first I’d read their…

New applets page

Over the last few years I’ve made quite a few web applets. But they have been scattered all over the place. As a good end-of-semester project I decided to consolidate all of them and create an applets page. Enjoy.

Cobweb plots for the logistic map: a Geogebra applet

A few days ago I posted Geogebra applets illustrating discrete dynamical systems. I was using these in a differential equations lecture that I gave. In the next lecture I showed the students how to draw cobweb plots for 1-dimensional discrete dynamical systems. A discrete dynamical system is a function in which the range is a…

An applet illustrating a continuous, nowhere differentiable function

Open any calculus book and you will find a discussion about how differentiability implies continuity, but continuity does not imply differentiability. The absolute value function is the standard example of a continuous function that is not differentiable (at ). The inquisitive student may ask: how bad can continuous, nondifferentiable functions get? Can we make a…