Continuous Everywhere but Differentiable Nowhere

Update: Bill Fitzgerald and Dan Meyer are now on a similar quest.
Yahoo has started a new web 2.0 site for helping teachers create, manage, and share “projects.” I’ve dreamed of a site where teachers collaborate (as well as beg, borrow, and steal) online in a massive community. Yeah, bloggers read and comment, but that’s not [...]

Introducing trigonometry has become even more of a challenge than I thought. I think about each part of the lesson really hard; I want to give it a flow and focus on teaching the concepts. What I don’t want trigonometry to be is a huge mess of ad hoc rules.
Today was my introduction to radians. [...]