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Math Puzzle

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  • A Atlantys

    The largest number I can do is: 4194304 (2^22). But, you want ANY positive number.... and only 3 twos.. not 4 twos.. or 5 twos, just 3? I strongly doubt it. Then again, I have been known to be wrong, from time to time. ;P I prefer to wear gloves when using it, but that's merely a matter of personal hygiene [Roger Wright on VB] Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning. [Rich Cook]

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    Ryan Binns
    wrote on last edited by
    #9

    Atlantys wrote: The largest number I can do is: 4194304 (2^22) Really?! What about 222! = approx 1.12*10426

    Ryan

    "Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late" John Nichol "Point Of Impact"

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    • R Ryan Binns

      Atlantys wrote: The largest number I can do is: 4194304 (2^22) Really?! What about 222! = approx 1.12*10426

      Ryan

      "Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late" John Nichol "Point Of Impact"

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      Dominik Reichl
      wrote on last edited by
      #10

      An even larger number exists :-D:-D -Dominik


      _outp(0x64, 0xAD); and __asm mov al, 0xAD __asm out 0x64, al do the same... but what do they do?? ;)

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      • R Ryan Binns

        Atlantys wrote: The largest number I can do is: 4194304 (2^22) Really?! What about 222! = approx 1.12*10426

        Ryan

        "Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late" John Nichol "Point Of Impact"

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        Dominik Reichl
        wrote on last edited by
        #11

        Umm, how many operators may I use? Because if I have an infinite number of operators, I can make an infinite long number... Btw, the number I thought of before was ((2 << 22)!) Where << is binary left shift. Now if I have an infinite number of operators, why not make (((((((((((((2 << 22)!)!)!)!)!)!)!)!)!)!)!)!) ... :confused: -Dominik


        _outp(0x64, 0xAD); and __asm mov al, 0xAD __asm out 0x64, al do the same... but what do they do?? ;)

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        • R Ryan Binns

          Atlantys wrote: The largest number I can do is: 4194304 (2^22) Really?! What about 222! = approx 1.12*10426

          Ryan

          "Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late" John Nichol "Point Of Impact"

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          xxrl
          wrote on last edited by
          #12

          ghost!;) You are the best!Me too!

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          • D Dominik Reichl

            Umm, how many operators may I use? Because if I have an infinite number of operators, I can make an infinite long number... Btw, the number I thought of before was ((2 << 22)!) Where << is binary left shift. Now if I have an infinite number of operators, why not make (((((((((((((2 << 22)!)!)!)!)!)!)!)!)!)!)!)!) ... :confused: -Dominik


            _outp(0x64, 0xAD); and __asm mov al, 0xAD __asm out 0x64, al do the same... but what do they do?? ;)

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            Ryan Binns
            wrote on last edited by
            #13

            Aah yes, but the goal of the problem is to specify any number using three 2's and any mathematical operators, not necessarily the largest number. Say the number is n, then n = 2log2(n), but I'm not sure if this is what is wanted. Any number can be represented by either 2n or 2n+2/2, but again I'm not sure if this is what is wanted. I dunno. I'm working on it :)

            Ryan

            "Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late" John Nichol "Point Of Impact"

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            • R Ryan Binns

              Atlantys wrote: The largest number I can do is: 4194304 (2^22) Really?! What about 222! = approx 1.12*10426

              Ryan

              "Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late" John Nichol "Point Of Impact"

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              Ludvig A Norin
              wrote on last edited by
              #14

              Well then, try (2^22)! .... that ought to be quite big. Btw. the question was how to write any number, not the biggest... Part of the non-smoking generation since 12/5-2003 22.35.
              -- Opinions expressed do not neccecarily reflect those of my -- employer; I do think for myself. Resisting temptation is -- easier when you think you'll maybe get another chance -- later on.

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              • L Ludvig A Norin

                Well then, try (2^22)! .... that ought to be quite big. Btw. the question was how to write any number, not the biggest... Part of the non-smoking generation since 12/5-2003 22.35.
                -- Opinions expressed do not neccecarily reflect those of my -- employer; I do think for myself. Resisting temptation is -- easier when you think you'll maybe get another chance -- later on.

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                Ryan Binns
                wrote on last edited by
                #15

                Ludvig A. Norin wrote: Btw. the question was how to write any number, not the biggest... Yes I know. I was just surprised he couldn't get anything bigger :). See my reply to Dominik above :)

                Ryan

                "Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late" John Nichol "Point Of Impact"

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                • S Shree

                  How can you write any positive integer using only three 2s and any mathematical operations?

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                  Joaquin M Lopez Munoz
                  wrote on last edited by
                  #16

                  0 is simple, so is 1. For the rest: n=-log2[log2(sqrt(sqrt(...n times...(2)...))))] Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

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                  • J Joaquin M Lopez Munoz

                    0 is simple, so is 1. For the rest: n=-log2[log2(sqrt(sqrt(...n times...(2)...))))] Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

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                    Jorgen Sigvardsson
                    wrote on last edited by
                    #17

                    You have a degree in mathematics, don't you? :) -- I am on fire. Do you need a light?

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                    • J Joaquin M Lopez Munoz

                      0 is simple, so is 1. For the rest: n=-log2[log2(sqrt(sqrt(...n times...(2)...))))] Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

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                      carrie
                      wrote on last edited by
                      #18

                      haha, absolute genius :)

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                      • J Joaquin M Lopez Munoz

                        0 is simple, so is 1. For the rest: n=-log2[log2(sqrt(sqrt(...n times...(2)...))))] Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

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                        Ryan Binns
                        wrote on last edited by
                        #19

                        Well done :)

                        Ryan

                        "Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late" John Nichol "Point Of Impact"

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                        • J Joaquin M Lopez Munoz

                          0 is simple, so is 1. For the rest: n=-log2[log2(sqrt(sqrt(...n times...(2)...))))] Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

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                          Brad Jennings
                          wrote on last edited by
                          #20

                          Genius!:) Brad Jennings "You're mom is nice. Mind if I go out with her?" - Jörgen Sigvardsson

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                          • J Joaquin M Lopez Munoz

                            0 is simple, so is 1. For the rest: n=-log2[log2(sqrt(sqrt(...n times...(2)...))))] Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

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                            Shree
                            wrote on last edited by
                            #21

                            That's it!!

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                            • J Jorgen Sigvardsson

                              You have a degree in mathematics, don't you? :) -- I am on fire. Do you need a light?

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                              Joaquin M Lopez Munoz
                              wrote on last edited by
                              #22

                              No I don't :) I'm a electrical engineer, but used to be fond of these kind of quizzes when I was younger. Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

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                              • J Joaquin M Lopez Munoz

                                No I don't :) I'm a electrical engineer, but used to be fond of these kind of quizzes when I was younger. Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

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                                Jorgen Sigvardsson
                                wrote on last edited by
                                #23

                                Have you read Gödel Escher Bach - The Eternal Golden Braid? Your solution reminded me a lot of the authors (Hofstadter) representation of the natural numbers. He defined it by an axiom 0 (zero) and an operation S (successor). Your log/sqrt solution for simulating S gave me a flashback.. :) -- I am on fire. Do you need a light?

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                                • S Shree

                                  How can you write any positive integer using only three 2s and any mathematical operations?

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                                  Wesner Moise
                                  wrote on last edited by
                                  #24

                                  The answer would involve some constructed function f(x) that increases x by 1. Then, applying f(x) to itself would allow all the positive numbers be generated. IE, f(2) = 3, and f(f(2)) = 4, and f^n(2) = 2+n-1. Since 2 is the only number we are allow, f(2) is really the only possibility, unless you want to consider f(22) or f(222) or f(2/2) or etc, but then we wastes our valuable 2s. Some functions f(x) that satisfy, are: f(x) = -(~x) --> bitwise negation followed by arithmetic negation f(x) = combination of logs and sqrts of a prior post so, my solution, the first f(x), can obtain, for example, 5 which is -~-~-~2. Thanks, Wes

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                                  • S Shree

                                    That's it!!

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                                    Wesner Moise
                                    wrote on last edited by
                                    #25

                                    my answer -~-~...-~2 is simpler and requires only one 2.

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                                    • W Wesner Moise

                                      The answer would involve some constructed function f(x) that increases x by 1. Then, applying f(x) to itself would allow all the positive numbers be generated. IE, f(2) = 3, and f(f(2)) = 4, and f^n(2) = 2+n-1. Since 2 is the only number we are allow, f(2) is really the only possibility, unless you want to consider f(22) or f(222) or f(2/2) or etc, but then we wastes our valuable 2s. Some functions f(x) that satisfy, are: f(x) = -(~x) --> bitwise negation followed by arithmetic negation f(x) = combination of logs and sqrts of a prior post so, my solution, the first f(x), can obtain, for example, 5 which is -~-~-~2. Thanks, Wes

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                                      Ryan Binns
                                      wrote on last edited by
                                      #26

                                      Brilliant! Well done :)

                                      Ryan

                                      "Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late" John Nichol "Point Of Impact"

                                      1 Reply Last reply
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                                      • W Wesner Moise

                                        The answer would involve some constructed function f(x) that increases x by 1. Then, applying f(x) to itself would allow all the positive numbers be generated. IE, f(2) = 3, and f(f(2)) = 4, and f^n(2) = 2+n-1. Since 2 is the only number we are allow, f(2) is really the only possibility, unless you want to consider f(22) or f(222) or f(2/2) or etc, but then we wastes our valuable 2s. Some functions f(x) that satisfy, are: f(x) = -(~x) --> bitwise negation followed by arithmetic negation f(x) = combination of logs and sqrts of a prior post so, my solution, the first f(x), can obtain, for example, 5 which is -~-~-~2. Thanks, Wes

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                                        Shree
                                        wrote on last edited by
                                        #27

                                        Great!!

                                        1 Reply Last reply
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                                        • W Wesner Moise

                                          The answer would involve some constructed function f(x) that increases x by 1. Then, applying f(x) to itself would allow all the positive numbers be generated. IE, f(2) = 3, and f(f(2)) = 4, and f^n(2) = 2+n-1. Since 2 is the only number we are allow, f(2) is really the only possibility, unless you want to consider f(22) or f(222) or f(2/2) or etc, but then we wastes our valuable 2s. Some functions f(x) that satisfy, are: f(x) = -(~x) --> bitwise negation followed by arithmetic negation f(x) = combination of logs and sqrts of a prior post so, my solution, the first f(x), can obtain, for example, 5 which is -~-~-~2. Thanks, Wes

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                                          Wesner Moise
                                          wrote on last edited by
                                          #28

                                          Regarding, my answer, -~-~-~ ... -~2, it is can be done with log n operations by appropriate using replacing some of the inner operations with the sqr or factorial functions. Thanks, Wes

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