Posts tagged math history
What’s the Deal with EuclidR...
An illustration from Oliver Byrne’s 1847 edition of Euclid’s Elements. Euclid’s fourth postulate states that all the right angles in this diagram are congruent. Image: Public domain, via Wikimedia Commons.
Why the heck do we need a postulate that says that all right angles are equal to one another? You probably remember lear [...]
The Math Wars, Lewis Carroll Style
Lewis Carroll in 1863, photographed by Oscar Gustave Rejlander. Image: Public domain, via Wikimedia Commons.
Carroll’s book was a salvo in the “math wars” of the day, the subject of which was how best to teach geometry. Euclid was the standard textbook in private schools that taught mathematics, but many people found it wanting. To them, it w [...]
Chasing the Parallel Postulate
If you’d like to see these again, you’d better accept the parallel postulate. Image: Webber, via Wikimedia Commons.
Euclidean geometry, codified around 300 BCE by Euclid of Alexandria in one of the most influential textbooks in history, is based on 23 definitions, 5 postulates, and 5 axioms, or “common notions.” But as [...]
Hyperbolic Quotes about Hyperbolic Ge...
“The treatise itself, therefore, contains only twenty-four pages—the most extraordinary two dozen pages in the whole history of thought!”
This Hungarian postage stamp does not depict János Bolyai. No portraits of him survive. For more information about the “real face of János Bolyai,” click the picture to read Tamás Dé [...]
Exploding Myths about the History of ...
An illustration from Kepler’s Mysterium Cosmographicum. This image from From the book, “The Science-History of the Universe” by Francis Rolt-Wheeler is in the public domain in the United States because it was published before January 1, 1923.
We want our heroes to be virtuous at all times, clear-thinking visionaries who neve [...]
10 Secret Trig Functions Your Math Te...
A diagram with a unit circle and more trig functions than you can shake a stick at. (It’s well known that you can shake a stick at a maximum of 8 trig functions.) The familiar sine, cosine, and tangent are in red, blue, and, well, tan, respectively. The versine is in green next to the cosine, and the exsecant is in pink to the right of [...]
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