Gary and Kenny Felder's Math and Physics Help Home Page Copyright© Gary and Kenny Felder

This is a collection of papers that we have written to explain various concepts in math and physics. But first, the obligatory list of links...

Jump down to the math papers Kenny's non-math related essays
Jump down to the Physics papers Our textbooks, Modern Physics and Mathematical Methods in Engineering and Physics


What you will find below are essays explaining various topics, more or less arranged from the most basic to the most advanced.

In addition to these essays, Kenny has also written a complete textbook for Advanced Algebra II. You can download the entire thing, or individual pieces and topics, for free, from the wonderful folks at Connexions at Rice University: go to

Gary and Kenny have also written a college-level textbook called Math Methods for Engineering and Physics. That book contains (among other things) "exercises" designed to facilitate active learning in that class. Click here to read more about the textbook, or click here to download the exercises for free.

Math and the Obvious (Kenny)

Negative Times Negative is What? (Kenny)

Base Eight And other math for people who are missing fingers (Kenny)

Triangles, Circles, and Waves (oh my!): An Overview of Trigonometry (Kenny)

Quick-and-Dirty Guide to the TI-83, TI-83+, TI-84, and TI-84+ (Kenny)

Quick-and-Dirty Guide to the NumWorks calculator (Kenny)

Kenny's Overview of Hofstadter's Explanation of Gödel's Theorem (Kenny)

How to Draw a Five-Dimensional Cube (Gary)

What dx Actually Means (Kenny)

Partial Fractions by Don Methven


Think Like A Scientist: An Induction Fable (Kenny)

Think Like a Physicist (Kenny, and my personal favorite)

One of These Things is Not Like the Other: A Discussion of Units (Kenny)

When Units Go Square (Kenny)

The Day the Universe Went All Funny: An Introduction to Special Relativity (Kenny)

Bumps and Wiggles: An Introduction to General Relativity (Gary)

General Relativity II: A Deeper Look (Gary)

Quantum Mechanics: The Young Double-Slit Experiment (Gary and Kenny)

Quantum Mechanics: What Do You Do with a Wavefunction? (Kenny and Gary)

Things Fall Apart: An Introduction to Entropy (Gary)

The Expanding Universe (Gary)

Beyond the Big Bang: Inflation and the Very Early Universe (Gary)

Spooky Action at a Distance: An Explanation of Bell's Theorem (Gary)

See Kenny's page of essays and commentaries (non-math related)

Contact Kenny at

Contact Gary at