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The New Coffee Room

  1. TNCR
  2. General Discussion
  3. Puzzle time

Puzzle time

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  • jon-nycJ Online
    jon-nycJ Online
    jon-nyc
    wrote on last edited by
    #2

    @Klaus said in Puzzle time:

    Find all natural numbers x and y such that the sum of the square roots of x and y is 2009.

    All the square roots or just the positive ones?

    Only non-witches get due process.

    • Cotton Mather, Salem Massachusetts, 1692
    KlausK 1 Reply Last reply
    • jon-nycJ Online
      jon-nycJ Online
      jon-nyc
      wrote on last edited by jon-nyc
      #3

      ||Assuming just the positive roots then itโ€™s just (1^2, 2008^2), (2^2, 2007^2), (3^2, 2006^2), ....etc.||

      Only non-witches get due process.

      • Cotton Mather, Salem Massachusetts, 1692
      taiwan_girlT 1 Reply Last reply
      • jon-nycJ jon-nyc

        ||Assuming just the positive roots then itโ€™s just (1^2, 2008^2), (2^2, 2007^2), (3^2, 2006^2), ....etc.||

        taiwan_girlT Offline
        taiwan_girlT Offline
        taiwan_girl
        wrote on last edited by
        #4

        |@jon-nyc

        ||I donโ€™t think your answer is correct. For example, the square root of one is one. And the square root of 2008 is almost 45. Add those two together and only equal 46

        Not sure of correct answer however. Lol46||

        1 Reply Last reply
        • jon-nycJ Online
          jon-nycJ Online
          jon-nyc
          wrote on last edited by jon-nyc
          #5

          @taiwan_girl

          ||You misread it. I squared those numbers for ease of notation and understanding the sequence. The real numbers would be (1, 4,032,064), (4, 4,028,049), (9, 4,024,036)...||

          Only non-witches get due process.

          • Cotton Mather, Salem Massachusetts, 1692
          taiwan_girlT 1 Reply Last reply
          • jon-nycJ jon-nyc

            @taiwan_girl

            ||You misread it. I squared those numbers for ease of notation and understanding the sequence. The real numbers would be (1, 4,032,064), (4, 4,028,049), (9, 4,024,036)...||

            taiwan_girlT Offline
            taiwan_girlT Offline
            taiwan_girl
            wrote on last edited by
            #6

            @jon-nyc ah okay. ๐Ÿ‘๐Ÿป

            1 Reply Last reply
            • KlausK Offline
              KlausK Offline
              Klaus
              wrote on last edited by Klaus
              #7

              Sorry, I screwed up. The sum of those numbers should be the square root of 2009. I fixed it above. The previous version is trivial, as Jon pointed out.

              1 Reply Last reply
              • jon-nycJ jon-nyc

                @Klaus said in Puzzle time:

                Find all natural numbers x and y such that the sum of the square roots of x and y is 2009.

                All the square roots or just the positive ones?

                KlausK Offline
                KlausK Offline
                Klaus
                wrote on last edited by
                #8

                @jon-nyc said in Puzzle time:

                @Klaus said in Puzzle time:

                Find all natural numbers x and y such that the sum of the square roots of x and y is 2009.

                All the square roots or just the positive ones?

                Just the positive ones.

                1 Reply Last reply
                • AxtremusA Away
                  AxtremusA Away
                  Axtremus
                  wrote on last edited by
                  #9

                  ||Since the positive square root of 2009 is not a natural number, there is zero natural number for x and y such that they sum to the positive square root of 2009.||

                  1 Reply Last reply
                  • jon-nycJ Online
                    jon-nycJ Online
                    jon-nyc
                    wrote on last edited by
                    #10

                    Ax thatโ€™s not the problem. Iโ€™ll restate it:

                    Solve for sqrt(x) + sqrt(y) = sqrt(2009) where x,y are natural numbers

                    Only non-witches get due process.

                    • Cotton Mather, Salem Massachusetts, 1692
                    1 Reply Last reply
                    • jon-nycJ Online
                      jon-nycJ Online
                      jon-nyc
                      wrote on last edited by
                      #11

                      || (41 * a^2, 41 * b^2) where a,b are natural numbers with a+b=7.

                      Or to spell it out, (41,1476), (164,1025), (369,656) and then the three number pairs that have those numbers reversed||

                      Only non-witches get due process.

                      • Cotton Mather, Salem Massachusetts, 1692
                      1 Reply Last reply
                      • KlausK Offline
                        KlausK Offline
                        Klaus
                        wrote on last edited by
                        #12

                        That looks good, Jon. Can you show how you got that solution?

                        1 Reply Last reply
                        • jon-nycJ Online
                          jon-nycJ Online
                          jon-nyc
                          wrote on last edited by jon-nyc
                          #13

                          2009^1/2 simplifies to 7*sqrt(41)

                          So the two addends need to be in the form a * sqrt(41) and b * sqrt(41) with a and b summing to 7.

                          Only non-witches get due process.

                          • Cotton Mather, Salem Massachusetts, 1692
                          1 Reply Last reply
                          • KlausK Offline
                            KlausK Offline
                            Klaus
                            wrote on last edited by
                            #14

                            ๐Ÿ‘

                            1 Reply Last reply
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