Archive for November 2010
The axis of symmetry of a quadratic function
Posted by: Gary Ernest Davis on: November 27, 2010
Jim Tanton (@jamestanton ) Tweeted: “x=-b/(2a) ugh!For y=3x^2-12x+7 factor first 2 terms y=3x(x-4)+7 See x=0 & x=4 give same output. Axis of symm must be x=2.Try this on y=ax^2+bx+c!” This, in my experience, is a simple yet typical example of Jim’s thinking: highly relational and generally avoiding instrumental procedures. In this post I simply want […]
Should students memorize the quadratic formula?
Posted by: Gary Ernest Davis on: November 26, 2010
Recently, Dan Meyer @ddmeyer Tweeted: “@MmeVeilleux Sorry if that’s a letdown. I wouldn’t have a kid memorize the quadratic formula.” x So, the question this raises for me, and that I want to address in this post is: should teachers require students to memorize the quadratic formula? x x x The quadratic formula A quadratic […]
