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Pythagoras theorem

[edit]
Original - Animated geometric proof of the Pythagoras theorem
Reason
This visual proof is much easier to understand for the layperson than the algebraic ones. It is also useful for explaining the concept of a mathematical proof.
Articles in which this image appears
Pythagorean theorem, Mathematical Proof
Creator
Alvesgaspar
  • Support as nominator --Noodle snacks (talk) 02:35, 23 February 2010 (UTC)[reply]
  • Support Wow, never thought of it that way. How cool. Don't know how many times I've used that and never even considered this sort of proof. upstateNYer 02:39, 23 February 2010 (UTC)[reply]
  • Query: the "creator" field above seems to contradict the file history, which credits Alvesgaspar. Which is correct?-- Avenue (talk) 03:16, 23 February 2010 (UTC)[reply]
  • Oppose. Good EV, but the jerkiness of the movements puts me off. -- Avenue (talk) 03:16, 23 February 2010 (UTC)[reply]
    • There is a trade off with animated gif. Less jerky motion means more frames and a consequent large file size. Noodle snacks (talk) 03:43, 23 February 2010 (UTC)[reply]
      • Yes, and I can accept that the current version might have got the balance right when it was created back in 2007. However a sub-400K animated gif doesn't seem that big to me nowadays; I imagine we could make it a lot smoother without causing problems. But perhaps I'm wrong. Can anyone point me to a relevant guideline? -- Avenue (talk) 04:14, 23 February 2010 (UTC)[reply]
        • I'm not sure there is a guideline beyond what has been accepted in the past since animated gifs are not that common. Mediawiki can't resize them to smaller resolutions, so the article thumbnail is the same size as the image itself. This means that at current size it would take about a minute to load on a dialup connection. I really think commons should introduce flash support, but that is another matter. Noodle snacks (talk) 10:15, 23 February 2010 (UTC)[reply]
  • Support. Yes, it's jerky and could be more visually impressive (at a file size cost), but it's very valuable to both articles IMO and it's unrealistic to expect the same standards as still images when it comes to animations. Wish it came with a pause button though. It would benefit from being a bit slower. Ðiliff «» (Talk) 11:19, 23 February 2010 (UTC)[reply]
  • Support. Good quality and ev, and personally, the jerkiness doesn't worry me, and slows it down for me just a bit. SpencerT♦Nominate! 03:16, 26 February 2010 (UTC)[reply]
  • Comment the jerkyness needs to be sorted out. I'm not convinced that animation really helps, with these animations to truly convince myself I need to check that the distances match, especially in the last stage that the width of the two squares are really a and b, you need to check with the triangles above. This is actually easier with static images, compare an alternative proof shown right. With the static pictures I can check the required measurements.
    An alternative proof which is arguably simpler and more compelling
There is also a question of sourcing. To whom should this visual proof be credited? For a featured picture I would really expect good referencing. --Salix (talk): 20:35, 26 February 2010 (UTC)[reply]
There are ample references asserting that the theorem being proved in the animation is correct. The exact proof doesn't need a reference (it's a proof!). Noodle snacks (talk) 23:31, 26 February 2010 (UTC)[reply]
To be picky FPC #6:Is accurate. It is supported by facts in the article or references cited on the image page and the article gives the proof without reference, its even not clear in the article which of the two rearrangements the text is referring to. Anyway Cut the Knot does give references to the proof,
This and the next 3 proofs came from R. B. Nelsen, Proofs Without Words, MAA, 1993.
The first two pieces may be combined into one. The result appear in a 1830 book Sanpo Shinsyo - New Mathematics - by Chiba Tanehide (1775-1849), [H. Fukagawa, A. Rothman, Sacred Mathematics: Japanese Temple Geometry, Princeton University Press, 2008, p. 83].--Salix (talk): 00:15, 27 February 2010 (UTC)[reply]
  • Support -- Wow, what can I say? Thanks for the nomination, Noodle snacks. Yes, I believe that a much smoother animation is possible. But this was made the hard way, frame by frame with CorelDraw. Anyway I believe that the fundamental concept of the "proof" is transmitted. To whom should this particular proof be credited? I have no idea. -- Alvesgaspar (talk) 00:04, 28 February 2010 (UTC)[reply]


  • Comment:In general, dissection proofs such as these are visually appealing, but they often gloss over significant assumptions and should not be used as a substitute for more formal reasoning. In fact there are several dissection "proofs" that lead to obviously false results (See [1]). This type of proof does have a place though, especially to introduce the theorem to people who don't want to take an entire course in Euclidean geometry. On the file size vs. Jerkiness issue, I don't think file size can be dismissed simply because dial-up connections are going the way of the dinosaur. Now people access Wikipedia through cell phones and even as those connections get higher bandwidth there may be other technologies that come along where large file sizes cause problems.--RDBury (talk) 18:55, 2 March 2010 (UTC)[reply]
    • Missing square puzzle is an example of one that we have an article on. They usually work by having triangles with slightly different side length ratios. They usually rely on squares for counting area and the like too. In this case a single triangle is mirrored a number of times, so that problem is not going to happen. There is plenty of discussion about in the article section on the rigour of this type proof too I might add. Noodle snacks (talk) 22:12, 2 March 2010 (UTC) Noodle snacks (talk) 22:08, 2 March 2010 (UTC)[reply]

Promoted File:Pythagoras-2a.gif —Maedin\talk 18:09, 3 March 2010 (UTC)[reply]

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