http://plus.maths.org/content/os/issue30/features/quadratic/index
From astronomy, to car crashes to singing in the shower, the authors show how one of the most famous equations helps us out. For many young students, who can't let go of their cell phones, I like to remind them that they wouldn't have them without mathematics. This article shows how the quadratic equation lead to mathematical developments that allowed for cell phones, via imaginary numbers.
So, like I also tell my students, if you can't remember the quadratic equation get it tattooed on your wrist*! It deserves that special honor!
*I say that as a joke - I allow them to have a sheet of notes on tests to rewrite formulas and the likes.
