Saturday, July 12, 2003


Where Have All the Lisas Gone? is a New York Times article from a couple of days ago. It’s interesting to read how names get popular and how, after a while, they’re “worn out” and replaced by new popular names. Some of the trends which were described in the article are also noticeable in Germany, but not all of them. For example, you can’t name children for places or things (the article predicts that colour names are going to become popular) because there are rules for first names in Germany. Names have to be in the International Handbook of First Names in order to be accepted in Germany. And if you choose a name that works for both girls and boys, you have to choose a middle name that determines the sex of the person. While this may seem like a huge restriction to Americans, it really isn’t so bad, I think. And it does have the advantage that people cannot accidentally name their children like some kind of virus or bacteria (I’ve read some weird stories about first names…).


When do you learn how to factor or solve quadratic equations in highschool outside of Germany? Here, at least two methods are taught in 9th grade, and one of them is Vieta‘s theorem.

I’m baffled by the story posted in this MetaFilter thread. A highschool student supposedly discovered a “new” way to factor a quadratic equation, the teacher is astonished, tries it out on several equations and decides to teach it from now on. The funny thing is, the Lizzie method is equivalent to Vieta’s theorem, which you can easily verify in five minutes.

To me, it sounds like the teacher didn’t even try to prove the solution before deciding to teach it to other students. And doesn’t she now about Vieta’s theorem? The guy lived in the 16th century, so the theorem is not exactly brand new!

And another question: Does the author of the article even know what a quadratic equation is?

“The quadratic equation has befuddled high school students for decades. An intimidating problem fraught with square roots and X-variables, the methods for its solution involve countless steps that are difficult to remember, tedious to implement, and often leave students empty-handed. The quadratic equation is also something of a threshold; students who don’t master it generally find themselves near the terminus of their math education.”

Sounds like the author did in fact not master it…


Ein ganz nettes Lernprogramm zur Teilchenphysik bietet die Physikdidaktik der Uni Erlangen an.

2 thoughts on “Saturday, July 12, 2003

  1. Sam DeVore

    I would say that the majority of students in the US learn how to solve or factor quadratic eqs in 9th grade (age 13/14 or so) I would say that most of the teachers that I have worked with do not know of Vieta’s theorem (many of the textbooks do not). Though the one text that used as a supplement did us vieta as the framework for building to the formula.

    What a proof though, ‘the teacher tried it a few times and it worked…’ wow call me impressed by the thoroughness of that teacher. ‘snipper method’ give me a break. hey I’ll give you snipper quadratic equation or ooo how about a hp calculator that just does it…

    Love the metafilter thread, thanks

    hope all is well

    sam d

  2. Andrea Frick

    I’m surprised that Vieta’s theorem is not usually taught in the US. For equations with not too large integer coefficients it works pretty well; it’s a very fast method if you practice it a little bit.

    And it’s reassuring to hear that trying it a few times is not considered a proof in the US either.

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