When I first taught the quadratic formula I would make students memorize it. The problem was that only about 50% of my students would remember it for the test. Then a teacher, Josh Severin, sang the quadratic formula to the tune of “Pop Goes the Weasel” and I knew that I would have no problems with students memorizing this again. In fact it has worked better than I could have possibly imagined. 100% of my students can memorize the formula now. Mostly because listening to me sing it is such a traumatic experience. Here are the words . . . X equals negative “b” plus or minus the square root of “b” squared minus four “a” “c” all over two “a”. Not that memorizing the formula is as important as deriving the formula, but it is a nice thing to have memorized for those college entrance exams. The video of my singing is below. Listen at your own risk.
A harder example of factor by grouping.
Basic factor by grouping video.
After about 5 takes, I was able to almost get what I wanted to say in this video. The mathematical concept of a function is hard to convey in less than 5 minutes. Had to keep it pretty basic, and I hope there are not many errors.
Sketch the graphs of the line 2x – y = -2 and the parabola y = -x² – 4x + 1. Find the coordinates of any points of intersection with technology and with algebra methods. As student was requesting a video on how to do this, and I couldn’t find one already made online so here goes.
Find the equation of a line through the point (5,-2) and perpendicular to the line 2x + 5y = 7
In the video at the end I changed all of my signs by multiplying both sides of the equation by -1. The signs can’t just magically change.
Some traditional instruction on graphing the quadratic formula. Here is the cookbook approach. Going to be at a conference today, so here is the concept my Algebra III class is on right now. I Apologize for the poor sound quality. I did this video using the smart board recorder. Lots of static. It could be that my mic was turn off as well.