Cantor's proofs

A lot of my precalculus students today didn’t like and/or didn’t believe Cantor’s proofs of the denumerability of the rationals and the non-denumerability of the reals. A few articulated their disbelief; most were quiet and attentive, but how many of… Read More ›

Beware the Algebrator

Yes, there really is a product called The Algebrator. Their slogan is, “You Type in Your Homework Problem. Algebrator does the Rest!” Here is an excerpt from one of their ads. What’s wrong with this picture?

Amusing calculus book?

The pseudonymous Rudbeckia Hirta writes about “the most amusing book ever written about calculus”: The Historical Development of the Calculus, by C.H. Edwards. I know, you don’t think the competition for most amusing calculus book is very stiff, but I’m… Read More ›


Please read Graham Cormode’s review of the TV show, “Numb3rs” (which he claims is pronounced “Numbthreers” rather than “Numbers”). Brief excerpt: Given low initial expectations, it was probably one of the better attempts to show mathematical topics within the context… Read More ›

What math has taught him

Sam Hughes is the author of the Venn Diagram cited in my previous post. I also recommend his list of “Things mathematics has taught me”: That there are such things as unanswerable questions — indeed, provably unanswerable questions That Occam’s… Read More ›

An argument from continuity

Two sophomores approached my colleague Josh with a question: “How can we construct a fair 5-sided die?” Josh posed a prior question: Is it even possible to construct such a die? He fashioned an interesting argument from continuity: Consider two… Read More ›