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New Orleans teenagers found a new proof of the Pythagorean Theorem

keith-mcnulty.medium.com

181–190 of 287 posts

Re: New Orleans teenagers found a new proof of the Pythagorean Theorem

#181
post #165

Cool proof, though it doesn't consider the case where a=b. If so, the geometric series is non-converging since the ratio isn't less than 1. Geometrically, the construction wouldn't work because the sides A and C of the large "triangle" would be parallel to each other.

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Re: New Orleans teenagers found a new proof of the Pythagorean Theorem

#182
post #150

Earlier quoted context omitted.

Apparently (found this while reading an article on the girls' accomplishments) somebody proved sin^2x + cos^2x = 1 without using the Pythagorean theorem in 2009: https://forumgeom.fau.edu/FG2009volume9/FG200925index.html . I don't think the "uses trigonometry" part is hype. They do use the definitions and law of sines, they just cleverly avoid the parts of trigonometry that depend on the Pythagorean theorem.

I address this in my OP. If you watch the video of the proof, you will see that the "law of sines" is 1 step away from the ratio definition of sin. You just drop one altitude, apply the definition again to the similar triangles, and re-arrange. It is almost content free as a result -- I see no reason using this in a proof would have special significance. For example, the standard proof using similar triangles ( https…

Not at all - the hype part is that 2 teenagers derived a uniquely elegant proof that other highly-trained mathematicians had thus far failed to do so.

Any other claims seem to have been added by the media, not the teenagers themselves.

Re: New Orleans teenagers found a new proof of the Pythagorean Theorem

#183
post #172

Nice proof? I understand that beauty is in the eyes of those who watch. Maybe i am blind, but i wouldn't call that a beautiful proof.

Who said it's nice? A proof is a proof, beautiful or not.

The author of the article. You did read it didnt you?

"most beautiful and simplest trigonometric proof we have seen to date"

Re: New Orleans teenagers found a new proof of the Pythagorean Theorem

#184
post #165

Cool proof, though it doesn't consider the case where a=b. If so, the geometric series is non-converging since the ratio isn't less than 1. Geometrically, the construction wouldn't work because the sides A and C of the large "triangle" would be parallel to each other.

Geometrically, this happens when alpha is 45. The two lines in the diagram from the article will be parallel and never converge. 2*alpha = beta+alpha I was waiting for them to break this out into a special case or something but the article never did. Can't find any other material on this proof that mentions it

You can divide partial sums first and then take the limit at infinity instead summing first and then dividing.

Not sure how much that helps with "infinite triangle" with two 90deg and one 0deg angles.

That's btw how you get sin90=1 which doesn't have any geometrical sense when we consider finite triangles.

Or in case of triangle with 45, 45, 90 maybe you could just pick different angle than 90 to be 2alpha.

Re: New Orleans teenagers found a new proof of the Pythagorean Theorem

#185
post #164

Earlier quoted context omitted.

Your explanation is very clear, but I still think that the article is confusing about that. Note how the author sets the expecatations at the beginning of the article: "...the proof these young trailblazers have proposed might make a few established mathematicians eat their words. This is because their proof uses trigonometry." This wording implies to me that Jackson and Johnson are actually the first who came up wit…

I think any new proof of PT is pretty cool. it doesn't even have to be "elegant" or better than previous proofs. Just a new one. Will there at some point be a proof that all possible proofs of Pythagorean Theorem have been found. Or for any theorem? Is it possible to prove that all possible proofs of something have been found?

I wonder, are there an infinite number of proofs of the theorem, each more complex than the last? Can I rephrase what they did, make it more convoluted, and call it a new proof?

Re: New Orleans teenagers found a new proof of the Pythagorean Theorem

#186

Earlier quoted context omitted.

That's what centuries of oppression does. It makes this rare. Hopefully, elevating these achievements in the community can make a difference. Ignoring that this problem exists certainly won't. If you don't care about broadening the pool of mathematicians, simply ignore the part of the article about that subject.

It doesn’t need to be mentioned though. I’m Asian if I read an Asian name doing something that Asians don’t normally do (like the recent accolades for Everything Everywhere), it’s going to inspire me. You don’t have to point it out. The people who need to hear it are not dumb. Mentioning it just sounds pandering and cringy.

Publicly stating that it doesn't matter sounds pandering and cringey to me. Pretending that you would be inspired by an Asian doing mathematics sounds even more pandering cringey. If the proof came from the adult sons of educated Asian immigrant parents in Boston, it would be far less newsworthy.

For people who care about speeding up progress in mathematics, the fact that this comes from a marginalized group is worthy of mention to understand how to repeat it. For everybody else, ranting about how it doesn't matter is simply off-topic flamebait utilized by culture warriors and their dupes.

Re: New Orleans teenagers found a new proof of the Pythagorean Theorem

#187
post #34

It would be really interesting to see if this could be applied to other analogous scenarios that are sometimes called Pythagorean theorems, in particular I’m thinking of the Pythagorean Theorem of Information Geometry- p* = argmin p of P (a set of possible distributions) of D_KL (p||q) (where q is eg your model's distribution)

You're missing the actual theorem in your comment, but the one you are referring to is essentially the pythagorean theorem for Bregman divergences, which I think may be a bit too far removed from geometry to allow this proof to generalize.

Ah, was just a flicker in my mind. Thanks - though I will ask, is there anything like the law of sines/cosines (in high dimensional statistics) that could get you to at least the first step of the proof?

Re: New Orleans teenagers found a new proof of the Pythagorean Theorem

#188
Nice trick, but this text only handles the case of “When our extended lines from steps 2 and 3 meet”. What if they don’t, that is, what if α = β = π/4, and the triangle is isosceles and rectangular?

I haven’t seen the original text, but this proof may be incomplete.

Re: New Orleans teenagers found a new proof of the Pythagorean Theorem

#189
I think Pythagorean theorem can be seen as a foundational concept for trigonometry since it is equivalent to sin squared x + cos squared x = 1. Still its impressive that the students were able to do this, but it's important to keep in mind that mathematicians weren't completely stumped by this for 2000 years.

Re: New Orleans teenagers found a new proof of the Pythagorean Theorem

#190

[flagged]

> When I read "New Orleans teenagers" I wanted to immediately give the benefit of the doubt, but a part of me suspected they may lead with identity. I didn’t have this reflexive reaction, but I can understand why one might if familiar with the way regional references can be coded language. That said, > It does a disservice to an achievement, if in fact there is one. A part of me is now sort of doubtful that this isn'…

> The difference is that the author seems to recognize that wishing doesn’t make it so, that systemic and historical barriers don’t vanish if you don’t mention them.

Also cultural. Don't underestimate how big a headwind an anti-education subculture can be to the people in it!

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