Matrices!

Matrices! In Algebra! Whoa! As you may be able to tell, I was surprised and delighted to find we were learning about matrices in class today. Not baby matrix math either. We were adding, subtracting, and multiplying. Multiplying! Multiplying matrices! Matrices! We even covered the idea of a transformation matrix and used one to scale the points of a triangle. The few students I was able to sit down with today got to hear about how matrices are used a lot in computer graphics. A couple students asked about programming games for their calculators. When I said "you could download them, or you could make them yourself" they seemed amazed at the thought that a person could actually program a video game.

"How do you think video games are made? Of course people program them!" Incidentally, my college roommate, Matt*, recently left his game development job to start a game development company. Check out a demo of their new game here! I wish I could bring up youtube links in real life. Until then, I guess retroactively posting on my blog will have to do.

Despite how difficult I find matrix math to be (there are lots of additions, which I think is the hardest part of math), matrix multiplication is easy to algorithm-ize. Give students a recipe, and BAM, they get it. Initially I was surprised how after 2 examples, everyone I talked to was able to multiply 2x2 by 2x3 matrices and 2x3 by 3x3 matrices without error. Perhaps it was the straightforwardness of the work. Compare this to solving 2x+4=y for x, which can be done many ways and still confuses some students. Maybe there's a lot to be said for not having choices.

This partnership program has inspired me to write a math book. I imagine anyone that has had a similar experience has thought similarly. So, how do you write a math book that's fun, useful, and free?