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mathematicsprof's profile
math prof
math prof
math prof
@mathematicsprof

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math prof

@mathematicsprof

I am a professor of mathematics with interests in partial differential equations.

pinterest.com/mathematicsprof
Joined April 2009

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    1. math prof‏ @mathematicsprof 20h20 hours ago

      In calc when teaching the 'min surface area of a can with given vol, of which soln is diameter = ht, I wrote a cat foot company telling them how much they'd save by making their cans taller. Got a letter from the marketing dept telling me a million reasons for the can's design.

      26 replies 83 retweets 369 likes
    2. David Feldman‏ @DavidFeldman 19h19 hours ago
      Replying to @mathematicsprof

      As others have said, if you still have it, please share the letter. I'd love to use it the next time I teach Calc I.

      3 replies 2 retweets 40 likes
      math prof‏ @mathematicsprof 17h17 hours ago
      Replying to @DavidFeldman

      pic.twitter.com/dSrwtlnwGy

      6:15 PM - 25 Nov 2018
      • 90 Retweets
      • 556 Likes
      • Kalium! ^_^ Bill Stephen `Pre💲heaf` Lazaro Computerfreund 🏴 ~"invisible chaotic self-modifying biomachine" Chris Peterson Katie O'Nell 🧠💻 Thamarasee Jeewandara Dylan
      9 replies 90 retweets 556 likes
        1. New conversation
        2. Jennifer Sage 🚴🏻‍♀️ 😺 🍷 ⛷‏ @vivavelo 13h13 hours ago
          Replying to @mathematicsprof @DavidFeldman

          so...were they correct?

          1 reply 0 retweets 7 likes
        3. math prof‏ @mathematicsprof 13h13 hours ago
          Replying to @vivavelo @DavidFeldman

          My letter to the cat-food company was more in jest. I realized there are many reasons for the size of a can of cat food other than the 'optimal surface area size.' I was interested in how they would respond. I think they had a lot of fun answering my query.

          4 replies 2 retweets 69 likes
        4. Jennifer Sage 🚴🏻‍♀️ 😺 🍷 ⛷‏ @vivavelo 13h13 hours ago
          Replying to @mathematicsprof @DavidFeldman

          it looks like they had fun. I'm impressed with their answer—though I'd have no idea if it were true or they just made it up! 😄 Or if they really do have very smart people working there.

          1 reply 0 retweets 6 likes
        5. math prof‏ @mathematicsprof 10h10 hours ago
          Replying to @vivavelo @DavidFeldman

          No, I'm sure their responses were based on fact and that they weren't just making stuff up.

          1 reply 0 retweets 12 likes
        6. Peter Conroy‏ @ruhlax_guy 6h6 hours ago
          Replying to @mathematicsprof @vivavelo @DavidFeldman

          You probably made some engineer’s day when marketing fwd’d that email (letter?) asking for input. “I’ve been waiting 20 years for this question” as he rolls up his sleeves...

          0 replies 0 retweets 52 likes
        7. End of conversation
        1. New conversation
        2. Kurtis‏ @KurtisBacks 13h13 hours ago
          Replying to @mathematicsprof @DavidFeldman

          That doesn't read like it's from marketing. That reads like an exasperated engineer having to explain to yet another person without full understanding of the design parameters why the product is the way it is.

          4 replies 0 retweets 49 likes
        3. Kurtis‏ @KurtisBacks 13h13 hours ago
          Replying to @KurtisBacks @mathematicsprof @DavidFeldman

          I bet that letter caused some poor engineer some serious pain when some executive came to him, letter in hand, and asked why the hell they were pissing away company money on excess material.

          1 reply 0 retweets 18 likes
        4. M‏ @is_M_is 12h12 hours ago
          Replying to @KurtisBacks @mathematicsprof @DavidFeldman

          Don't be silly, packaging technical experts barely ever to complete that many sentences in a row before someone runs away, that person was thrilled 😄

          1 reply 0 retweets 27 likes
        5. Kurtis‏ @KurtisBacks 12h12 hours ago
          Replying to @is_M_is @mathematicsprof @DavidFeldman

          OK, Tim, we need a container that is durable, easy to open, lightweight, can withstand temperatures high enough to heat treat the product inside, is food safe, and space efficient. Oh, and marketing wants it to be a purple pyramid.

          2 replies 0 retweets 20 likes
        6. razumny‏ @razumny 10h10 hours ago
          Replying to @KurtisBacks @is_M_is and

          Can do! http://de.academic.ru/pictures/dewiki/116/tetra_pak_2008.jpg …

          0 replies 0 retweets 5 likes
        7. End of conversation
        1. Nils-Arne Dahlberg‏ @UncleBod 15h15 hours ago
          Replying to @mathematicsprof @DavidFeldman

          Reality has often more parameters than you can imagine...

          0 replies 3 retweets 19 likes
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        1. Roshan‏ @roshanonline 16h16 hours ago
          Replying to @mathematicsprof @DavidFeldman

          This needs to be a case study in a product design/packaging class.

          0 replies 1 retweet 25 likes
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        1. Skyfur‏ @myshanks 16h16 hours ago
          Replying to @mathematicsprof @DavidFeldman

          Good they have a reason as solid as yours

          0 replies 0 retweets 10 likes
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        1. Sam Jaques‏ @sejaques 8h8 hours ago
          Replying to @mathematicsprof @DavidFeldman

          This is great but cans of human food have all the same constraints yet are much closer to the minimum surface area. What’s different about cat food? Is it just that the end user tries to shove their whole face into the can?

          0 replies 0 retweets 4 likes
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        1. MazeEngineers‏ @MazeEngineers 7h7 hours ago
          Replying to @mathematicsprof @DavidFeldman

          I think this is the first time I've seen a business 'win' a debate with these smart-alec letters!

          0 replies 0 retweets 0 likes
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        1. New conversation
        2. Richard Litherland‏ @RickLitherland 11h11 hours ago
          Replying to @mathematicsprof @DavidFeldman

          The textbook we currently use (Stewart) has an extended exercise that addresses points 4 and (more-or-less) 2, but not the others. The conclusion is that optimal sizes vary from h=d to tall and thin, which completely fails to account for tuna cans.

          1 reply 0 retweets 0 likes
        3. James Tiberius Shirtless Kirk  🚀‏ @ShirtlessKirk 10h10 hours ago
          Replying to @RickLitherland

          apparently h<d are easy to sterilise, just like h>d ones. Somehow h=d ones occupy their own set of awkwardness. Alternatively, that's bollocks, like the "it takes too long to switch both height and diameter when processing" (what, like tuna cans?)

          1 reply 0 retweets 1 like
        4. Richard Litherland‏ @RickLitherland 9h9 hours ago
          Replying to @ShirtlessKirk

          That's probably right, though why sterilisation cost should be the dominant factor I don't know. Presumably a can with an inverse h/d ratio would do as well for sterilisation, but it would be impossible to empty.

          1 reply 0 retweets 1 like
        5. 1 more reply
        1. Trucker Carlson  🇺🇸‏ @CarlsonTrucker 12h12 hours ago
          Replying to @mathematicsprof @DavidFeldman

          That’s a bold cat food can response

          0 replies 0 retweets 1 like
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