• PM_ME_VINTAGE_30S [he/him]@anarchist.nexus
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      1 day ago

      The math one uses the fact that 1 + 2 + 3 + … “=” -1/12, where the equality is in the sense of Ramanujan summation. Classically, the series diverges, so using the equality sign is a bit deceptive. However, in some contexts, it is meaningful to assign a sum to divergent series.

      • khannie@lemmy.world
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        20 hours ago

        Feels like a risky click. I’m not sure my worldview can take any more shattering. It’s already shattered I tell you. SHATTERED.

      • Klear@piefed.world
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        1 day ago

        Oh, good. There’s a Numberphile video on it linked at the end. That gives me much better odds of understanding this than just reading the article.

        • PM_ME_VINTAGE_30S [he/him]@anarchist.nexus
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          1 day ago

          Actually, the Numberphile video is notorious for lacking mathematical rigor. Mathologer did a video on it. IMO, it’s really really important to explain the difference between what’s going on here (assigning a number to a divergent series) and what we ordinarily do (computing the limit of a sequence of partial sums).

          • i_love_FFT@jlai.lu
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            20 hours ago

            There was a full on mathematical war on YouTube, with numberphile coming back later to show that most partial sum methods also end up at -1/12.

            As a science nerd, mathologer basically just took the camp of “old concensus” and gave no other argument than “this is alien math, nope, I don’t like it”. It just felt like mathologer was Pythagoras fighting against irrational numbers…

            • PM_ME_VINTAGE_30S [he/him]@anarchist.nexus
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              16 hours ago

              As a science nerd, mathologer basically just took the camp of “old concensus” and gave no other argument than “this is alien math, nope, I don’t like it”.

              I mean maybe in the first video, but not the one I linked. Here, he was very precise about the mistakes Numberphile made in the presentation, and the purpose and utility of standard summation of convergent series versus the other methods of summation. Like he’s not dissing the idea or utility of summing divergent series literally at all, just Numberphile’s oversimplified presentation of it.

              • i_love_FFT@jlai.lu
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                15 hours ago

                Yeah that’s fair! I didn’t get through some of his videos, being more of a downer “grumpy style” 😉

                I’ll try to watch that again

        • NeatNit@discuss.tchncs.de
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          1 day ago

          There have been some claims that the numberphile video is very misrepresentative of the underlying math. But I never dug deep enough into it.

  • rumba@lemmy.zip
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    1 day ago

    And that -1/12 bs is why I cannot math.

    1+2+3 … tends toward infinity and there’s no amount of playing with numbers will convince me otherwise.

    • bort@sopuli.xyz
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      1 day ago

      And that -1/12 bs is why I cannot math.

      it’s not actually math. It’s people coming up with alternative definitions and then feeling smug when their alternative definitions give weird results.

    • Maturin [any]@hexbear.net
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      1 day ago

      1+2+3… absolutely diverges to infinity. In order to get the -1/12 result you have to explicitly suspend the normal rules governing math in very specific ways. Some YouTubers for clickbait effect pretend that you are not suspending the rules to get that result. However, suspending the rules in the ways that allow for -1/12 demonstrates all these patterns that are also cool if you are a big enough nerd to think number manipulation like that is cool.

    • TwilightKiddy@programming.dev
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      1 day ago

      Hello, I play with numbers:

      1+2+3+...=S
      S-S=1+2+3+4+...
           -1-2-3-...=
      1+1+1+1+...=S-S=0
      

      Moral of the story: ones together are nothing.

      Thank you for your attention.

      • rumba@lemmy.zip
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        23 hours ago

        let me hand you a tissue, looks like you got some ‘stuff’ in your text box

      • jaybone@lemmy.zip
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        22 hours ago

        lol 1-1, 2-2 etc.

        How do you get 1 + 2-1?

        You need to distribute that minus sign to all numbers in the sequence. You can’t leave off the first one.

        • TwilightKiddy@programming.dev
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          21 hours ago

          It’s an infinite series, love, I just moved it, there are still enough elements in them because, well, they are infinite. If you are so sad about it, write the second one as 0-S, changes nothing but now you have a donut to pair up with the 1 in the first series.

        • prime_number_314159@lemmy.world
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          21 hours ago

          He has a plus one, and a minus one, a plus two, and a minus two, and so on. This is analogous to how conditionally convergent series can be modified to give any finite (or infinite) sum merely by changing the order of the terms.

  • crwth@piefed.zip
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    1 day ago

    I had a student tasked with summing a finite geometric sequence with |r|>1, let’s say 1+2+4+8+16. He had apparently forgotten the formula for that, but knew the formula for the infinite series a/(1-r). Good enough he thinks, and sums 1+2+4+… = -1, then subtracts off the excess terms 32+64+128+… = -32, and gets the correct answer of 31.

  • Nima@leminal.space
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    1 day ago

    i thought the first one ended with “after 4 orders the bartender says ‘you guys suck’ and pours two beers.”

  • SwingingTheLamp@piefed.zip
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    1 day ago

    This bar’s pricing makes no sense whatsoever. One beer is $1. One and 3/4 beers is also $1. Maybe they round down? Then, everybody should order 0.9999… beer, except that for some reason seventy-two beers is -$1? Weird.

    • sepiroth154@feddit.nl
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      1 day ago

      They mean that the sequences go on forever, but the joke definitely doesn’t make that clear.

      • SwingingTheLamp@piefed.zip
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        1 day ago

        Too subtle a joke, I guess. The description is just missing “and so on.” But the “and so on” is the crux of the bullshit in the mathematical “proof” referenced.