This is a summary of my talk at the conference Celebrating the Centenary of James H. Wilkinson's Birth at the University of Manchester, May 29.... read more >>

Why are manhole covers round? It is so they won't fall through the hole they are intended to cover. They have the same diameter regardless of where it is measured. If the hole has a slightly smaller diameter, it is not possible to orient the cover so that it will fall through. A square or rectangular cover can be turned slightly and it will easily fit through the hole.... read more >>

In a comment following my post about half-precision arithmetic, "Raj C" asked how the parameters for IEEE Standard 754 floating point arithmetic were chosen. I replied that I didn't know but would try to find out. I called emeritus U. C. Berkeley Professor W. (Velvel) Kahan, who was the principle architect of 754. Here is what I learned.... read more >>

As the degree of an interpolating polynomial increases, does the polynomial converge to the underlying function? The short answer is maybe. I want to describe a visual tool to help you investigate this question yourself.... read more >>

Two months ago I wrote a blog post about Teaching Calculus to a Deep Learner. We wrote the code for that post in one afternoon in the MathWorks booth at the SIAM Annual Meeting. Earlier that day, during his invited talk, MIT Professor Gil Strang had spontaneously wondered if it would possible to teach calculus to a deep learning computer program. None of us in the booth were experts in deep learning.... read more >>

I probably first saw this matrix in 1960 in John Todd's class at Caltech. But I forgot about it until Tahar Loulou jogged my memory with a comment following my blog post in late May. It deserves a place in our gallery of interesting matrices.... read more >>

MIT's Professor Gil Strang gave two talks in one morning recently at the SIAM annual meeting. Both talks derived from his experience teaching a new course at MIT on linear algebra and neural nets. His first talk, "The Structure of a Deep Neural Net", was in a minisymposium titled "Deep Learning and Deep Teaching", which he organized. Another talk in that minisymposium was by Drexel's Professor Pavel Grinfeld on "An Informal Approach to Teaching Calculus." An hour later, Gil's gave his second talk, "Teaching About Learning." It was an invited talk at the SIAM Conference on Applied Mathematics Education.... read more >>

Here are the first 12 integers from an infinite sequence defined by a deceptively simple rule. Can you see the pattern? Try to predict the next number in the sequence.... read more >>

If you follow this blog regularly, you know that I love fractals. I recently spent a pleasant afternoon in Nashua, New Hampshire, where my daughter Teresa introduced me to Gregory Searle, a fractal artist and computer geek. Here is his logo.... read more >>

Today is Easter Sunday. Why? How is the date of Easter determined?... read more >>