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Replies: 6   Last Post: Apr 10, 1996 11:09 AM

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 DCOOK@dmail.dartnet.peachnet.edu Posts: 10 Registered: 12/3/04
Posted: Apr 10, 1996 3:43 AM

From: Jeffrey Darrow <darrowj@howland.isu.edu>
Date: Tue, 9 Apr 1996 17:40:14 -0400
To: math-history-list@maa.org

Today I had a student in my college algebra class ask me why
"Quadratic Equations" are so named. If we have a polynomial of
degree 3 set equal to zero, we call it a cubic equation and that
makes sense to these students. However, this particular student is
curious because she sees "Q-U-A-D" in quadratic and thinks of four,
yet the polynomial in such an equation is only of degree 2. I've
never encountered this question before and I was at a loss for an
explanation. Does anyone know the origin of the term "quadratic

Jeff Darrow
Idaho State University

Jeff,
Look in Chapter V of "The Great Art or Rules of Algebra' by Girolamo
Cardano, translated and edited bt T. Richard Witmer, MIT 1968. When he
says to complete the square, he really means to complete a geometric
square. Cardano gives the proper credit to Euclid in II, 4 of the
elements. Euclid solved quadratic equations geometrically and x^2
( x square ) really was a square evan though we use a 2.
Peace,
Don Cook

Date Subject Author
4/9/96 Jeffrey Darrow
4/9/96 Pat Allaire
4/9/96 John Conway
4/9/96 F. Alexander Norman
4/9/96 Jeffrey Darrow
4/10/96 DCOOK@dmail.dartnet.peachnet.edu
4/10/96 John Conway