Feb 202017
Intercepts and Asymptotes and Holes, Oh My!

I've been teaching for 27 years. This morning during a discussion of rational functions in a precalculus class, I had one of those why-didn't-I-think-of this-years-ago moments, when I found myself drawing a Venn diagram on the board in response to massive confusion about holes. My hypothesis about why the analysis of rational functions can feel so overwhelming to beginners [...]

Jul 242016
Making Sense of Exponential Models

Exponential growth is a topic that deserves especially thoughtful treatment as part of a high school education because a person who has thought deeply about this ubiquitous phenomenon pays attention to and conceptualizes certain critical issues in, for example, science, economics, and social science, in a fundamentally different way than one who is oblivious to or overwhelmed by the concept. (For one [...]

Jan 092016
Quadratic Functions with Desmos Activity Builder

I thoroughly enjoyed using an activity I created using Desmos Activity Builder over the course of the past couple of days with my precalculus students to help them think in new ways about quadratic functions. These are intelligent people who have graphed plenty of parabolas and solved plenty of quadratic equations in Algebra 1 and 2, and have [...]

Mar 192015
Fresh eyes on end behavior of rational functions

Over the past few years of teaching precalculus regularly, I've experimented with a variety of approaches to rational functions in an attempt to find one that will result in students discovering and eventually truly understanding how the equation of a rational function determines its graph. I have never felt very successful. Too many students get confused somewhere along the way, come to [...]