Some odds and ends:
- The WebEquations link no longer works and was removed. The WriteLaTex link was moved as Sagemath Cloud, with support for Sage, is now the only tool you need.
- A helpful reader found some mistakes in the Trig formulas PDF posted on the Handouts page. The PDF and LaTeX code were fixed and I've updated those files.
- I've run across a nice post at Un peu de math which has a lot of interesting links to explore: a wiki with "...a gallery of all images — illustrations, diagrams and animations" created by LucasVB. I've already downloaded 2 animated gifs on radians that will be useful when I get to trig and one on the transpose of a matrix. A nice article on the use of computers in mathematical proofs from Quanta Magazine. Another link about computers in math and the "curse of computing". Of course the Sage Interacts on graph theory were nice, too.
An important point worth emphasizing from the above articles. Sage, being open source, can be checked for the accuracy of the code. Closed source mathematical programs are "black box"; the underlying code might be (and sometimes is) wrong, but how do you know until you spot the error.
Trusting closed source math programs violates the very spirit of math and science.