Free42 is a free, open source emulator of the HP 42s calculator that can be downloaded and used on an iPhone, Android, and Windows, Mac, or Linux computer. It is WONDERFUL! Once you get used to RPN notation it becomes an extension to your brain! This video is an introduction to the calculator for my physics and math courses for homeschoolers (available for digital download at http://mathwithoutborders.com). BTW, you don't need to be a homeschooler to teach yourself the parts of high school math (Algebra through Calculus) and physics you missed out on because you were a distracted teenager at the time! ... https://www.youtube.com/watch?v=UKvhBSJPw0o

This is part of the precalculus course in the Math Without Borders Home Study Companion series, based on the third edition of Paul A. Foerster's Precalculus with Trigonometry: Concepts and Applications. For more info on the course, check out http://www.mathwithoutborders.com. Sage is a powerful computation tool. It does symbolic and numerical processing and is useful at the university level and beyond. The main difficulty in using it with high school students is that most of the tutorials include such high-end topics that it is easy to become overwhelmed. This video selects out the matrix and vector topics needed for the work in Chapter 13 of Foerster's textbook, which deals with matrix transformations. I am posting it publicly because as a brief introductory tutorial it may be of interest to others as well. Some level of understanding of matrices is assumed in the explanations. For practice you can download the Sage file shown in the video and interact with it directly here: http://mathwithoutborders.com/wp-content/uploads/2012/07/download_worksheets.zip. Download, then unzip this file to your desktop, then start Sage, then upload the sws file (enclosed in the zip file) from your desktop into Sage. ... https://www.youtube.com/watch?v=GKuYyuBVXoU