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  4. Buster's math problem!

Buster's math problem!

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  • N Nish Nishant

    Solve for n :- n^n^n^n.........(infinite) = 2 Regards Nish p.s. You have only 300 seconds. After that the solution will be posted if no one has solved this


    Regards, Nish Native CPian. Born and brought up on CP. With the CP blood in him.

    N Offline
    N Offline
    Nish Nishant
    wrote on last edited by
    #6

    Solve for n :-

    n^n^n^n.........(infinite) = 2

    Solution :- Let x = n^n^n^n^n....(infinite) = 2 Now n^x = n^(n^n^n^n....) = n^2 But also n^x = n^(n^n^n^n...) = n^n^n^n^n... [we take out the brackets] Thus n^2 = n^n^n^n^n... Since n^n^n^n^n... = 2 We now have :- n^2 = 2 n = √2 (Square Root of 2 ) Nish


    Regards, Nish Native CPian. Born and brought up on CP. With the CP blood in him.

    C A 2 Replies Last reply
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    • N Nish Nishant

      Solve for n :-

      n^n^n^n.........(infinite) = 2

      Solution :- Let x = n^n^n^n^n....(infinite) = 2 Now n^x = n^(n^n^n^n....) = n^2 But also n^x = n^(n^n^n^n...) = n^n^n^n^n... [we take out the brackets] Thus n^2 = n^n^n^n^n... Since n^n^n^n^n... = 2 We now have :- n^2 = 2 n = √2 (Square Root of 2 ) Nish


      Regards, Nish Native CPian. Born and brought up on CP. With the CP blood in him.

      C Offline
      C Offline
      ColinDavies
      wrote on last edited by
      #7

      Sorry Nish your Answer doesn't compute with me :-( Regardz Colin J Davies

      Sonork ID 100.9197:Colin

      More about me :-)

      D 1 Reply Last reply
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      • N Nish Nishant

        Solve for n :- n^n^n^n.........(infinite) = 2 Regards Nish p.s. You have only 300 seconds. After that the solution will be posted if no one has solved this


        Regards, Nish Native CPian. Born and brought up on CP. With the CP blood in him.

        C Offline
        C Offline
        ColinDavies
        wrote on last edited by
        #8

        Nish - Native CPian wrote: Solve for n :- n^n^n^n.........(infinite) = 2 n = 1 + ( 1 / infinity ) Regardz Colin J Davies

        Sonork ID 100.9197:Colin

        More about me :-)

        N 1 Reply Last reply
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        • C ColinDavies

          Nish - Native CPian wrote: Solve for n :- n^n^n^n.........(infinite) = 2 n = 1 + ( 1 / infinity ) Regardz Colin J Davies

          Sonork ID 100.9197:Colin

          More about me :-)

          N Offline
          N Offline
          Nish Nishant
          wrote on last edited by
          #9

          ****Colin Davies wrote: n = 1 + ( 1 / infinity ) Reasonable :-) Nish


          Regards, Nish Native CPian. Born and brought up on CP. With the CP blood in him.

          C 1 Reply Last reply
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          • N Nish Nishant

            ****Colin Davies wrote: n = 1 + ( 1 / infinity ) Reasonable :-) Nish


            Regards, Nish Native CPian. Born and brought up on CP. With the CP blood in him.

            C Offline
            C Offline
            ColinDavies
            wrote on last edited by
            #10

            Nish - Native CPian wrote: Reasonable It appalls me :-( Regardz Colin J Davies

            Sonork ID 100.9197:Colin

            More about me :-)

            1 Reply Last reply
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            • C ColinDavies

              Sorry Nish your Answer doesn't compute with me :-( Regardz Colin J Davies

              Sonork ID 100.9197:Colin

              More about me :-)

              D Offline
              D Offline
              David Wengier
              wrote on last edited by
              #11

              How do you know? He is dividing both sides by "n^n^n^n^n.." to infinity. Surely that would take an infinite amount of time to compute :) What I love about this stuff, is how the infinite amount of numbers between 0 and 1, is larger than the infinte amount of numbers between 0 and infinity. -- David Wengier Sonork ID: 100.14177 - Ch00k

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              • N Nish Nishant

                Solve for n :-

                n^n^n^n.........(infinite) = 2

                Solution :- Let x = n^n^n^n^n....(infinite) = 2 Now n^x = n^(n^n^n^n....) = n^2 But also n^x = n^(n^n^n^n...) = n^n^n^n^n... [we take out the brackets] Thus n^2 = n^n^n^n^n... Since n^n^n^n^n... = 2 We now have :- n^2 = 2 n = √2 (Square Root of 2 ) Nish


                Regards, Nish Native CPian. Born and brought up on CP. With the CP blood in him.

                A Offline
                A Offline
                Alexandru Savescu
                wrote on last edited by
                #12

                Do you really mean that solution or are you just taking the piss? Best regards, Alexandru Savescu

                Richard DeemingR 1 Reply Last reply
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                • A Alexandru Savescu

                  Do you really mean that solution or are you just taking the piss? Best regards, Alexandru Savescu

                  Richard DeemingR Offline
                  Richard DeemingR Offline
                  Richard Deeming
                  wrote on last edited by
                  #13

                  It is correct, as long as you take the equation to read:

                  n ^ (n ^ (...

                  and not:

                  ((n ^ n) ^ n)...

                  Proof:

                  ∀ x > 1:
                  ∀ y > 1, x < x^y
                  ∀ 0 < y < 1, 1 < x^y < x
                  Limy → 1 x^y = x

                  Let x=2, p = 2y, n = √2 [= 2^½].

                  1 < n < 2
                  x^y = 2^(p/2) = n^p
                  ∀ 0 < p < 2, 1 < n^p < 2
                  ∀ p > 1, n < n^p
                  ∴ ∀ 1 < p < 2, n < n^p < 2
                  Limp → 2 n^p = 2

                  Let p0 = n, pi = n ^ pi-1:

                  1 < p0 < 2 ⇒ p0 < [n^p0 = p1] < 2
                  ∴ 1 < p0 < ... < pi-1 < pi < ... < 2
                  Limi → ∞ pi = 2

                  Elementary! :wtf: Richard

                  "These people looked deep within my soul and assigned me a number based on the order in which I joined" - Homer

                  C A 2 Replies Last reply
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                  • Richard DeemingR Richard Deeming

                    It is correct, as long as you take the equation to read:

                    n ^ (n ^ (...

                    and not:

                    ((n ^ n) ^ n)...

                    Proof:

                    ∀ x > 1:
                    ∀ y > 1, x < x^y
                    ∀ 0 < y < 1, 1 < x^y < x
                    Limy → 1 x^y = x

                    Let x=2, p = 2y, n = √2 [= 2^½].

                    1 < n < 2
                    x^y = 2^(p/2) = n^p
                    ∀ 0 < p < 2, 1 < n^p < 2
                    ∀ p > 1, n < n^p
                    ∴ ∀ 1 < p < 2, n < n^p < 2
                    Limp → 2 n^p = 2

                    Let p0 = n, pi = n ^ pi-1:

                    1 < p0 < 2 ⇒ p0 < [n^p0 = p1] < 2
                    ∴ 1 < p0 < ... < pi-1 < pi < ... < 2
                    Limi → ∞ pi = 2

                    Elementary! :wtf: Richard

                    C Offline
                    C Offline
                    ColinDavies
                    wrote on last edited by
                    #14

                    I agree if But It would have been documented differently, Also I admit I automatically assumed that, and considered it far too simple and logical. :-( Regardz Colin J Davies

                    Sonork ID 100.9197:Colin

                    More about me :-)

                    1 Reply Last reply
                    0
                    • N Nish Nishant

                      Solve for n :- n^n^n^n.........(infinite) = 2 Regards Nish p.s. You have only 300 seconds. After that the solution will be posted if no one has solved this


                      Regards, Nish Native CPian. Born and brought up on CP. With the CP blood in him.

                      L Offline
                      L Offline
                      Lost User
                      wrote on last edited by
                      #15

                      Nish - Native CPian wrote: n^n^n^n.........(infinite) = 2 equals to 2 or tends to 2?

                      N 1 Reply Last reply
                      0
                      • Richard DeemingR Richard Deeming

                        It is correct, as long as you take the equation to read:

                        n ^ (n ^ (...

                        and not:

                        ((n ^ n) ^ n)...

                        Proof:

                        ∀ x > 1:
                        ∀ y > 1, x < x^y
                        ∀ 0 < y < 1, 1 < x^y < x
                        Limy → 1 x^y = x

                        Let x=2, p = 2y, n = √2 [= 2^½].

                        1 < n < 2
                        x^y = 2^(p/2) = n^p
                        ∀ 0 < p < 2, 1 < n^p < 2
                        ∀ p > 1, n < n^p
                        ∴ ∀ 1 < p < 2, n < n^p < 2
                        Limp → 2 n^p = 2

                        Let p0 = n, pi = n ^ pi-1:

                        1 < p0 < 2 ⇒ p0 < [n^p0 = p1] < 2
                        ∴ 1 < p0 < ... < pi-1 < pi < ... < 2
                        Limi → ∞ pi = 2

                        Elementary! :wtf: Richard

                        A Offline
                        A Offline
                        Alexandru Savescu
                        wrote on last edited by
                        #16

                        Well it is not elementary enough :wtf: All your statements from above are correct except for the last one Richard_D wrote: 1 < p0 < 2 ⇒ p0 < [n^p0 = p1] < 2∴ 1 < p0 < ... < pi-1 < pi < ... < 2Limi → ∞ pi = 2 I agree for every i, 1 < pi < 2, but this does not mean that the limit is 2, It may be very well 1.8. You must also prove that for every x>0 there exists and k so that 2-x < pk < 2. ;) Another classic example is the definition of e: limit of (1 + 1/n)^n. All you can tell that for every n: 2 < (1 + 1/n)^n < 3 but the limit is not 3 is 2.718182.... Yet I tend to agree (my intuition) that the limit of our sequence p0, p1,...pn is 2. I'll look up into it. Best regards, Alexandru Savescu

                        Richard DeemingR 1 Reply Last reply
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                        • L Lost User

                          Nish - Native CPian wrote: n^n^n^n.........(infinite) = 2 equals to 2 or tends to 2?

                          N Offline
                          N Offline
                          Nish Nishant
                          wrote on last edited by
                          #17

                          Anonymous wrote: equals to 2 or tends to 2? Tends to 2 of course!!! Nish


                          Regards, Nish Native CPian. Born and brought up on CP. With the CP blood in him.

                          1 Reply Last reply
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                          • A Alexandru Savescu

                            Well it is not elementary enough :wtf: All your statements from above are correct except for the last one Richard_D wrote: 1 < p0 < 2 ⇒ p0 < [n^p0 = p1] < 2∴ 1 < p0 < ... < pi-1 < pi < ... < 2Limi → ∞ pi = 2 I agree for every i, 1 < pi < 2, but this does not mean that the limit is 2, It may be very well 1.8. You must also prove that for every x>0 there exists and k so that 2-x < pk < 2. ;) Another classic example is the definition of e: limit of (1 + 1/n)^n. All you can tell that for every n: 2 < (1 + 1/n)^n < 3 but the limit is not 3 is 2.718182.... Yet I tend to agree (my intuition) that the limit of our sequence p0, p1,...pn is 2. I'll look up into it. Best regards, Alexandru Savescu

                            Richard DeemingR Offline
                            Richard DeemingR Offline
                            Richard Deeming
                            wrote on last edited by
                            #18

                            OK, I haven't done real maths for four years! This may be total crap, but I'm thinking along these lines: [Trying to extend this to n^n^... = X ⇒ n = X ^ (1/X) ∀ X ∈ N]

                            p0 = X^(1/X), pi = p0 ^ pi-1

                            We already have:

                            ∀ i, 1 < pi-1 < pi < X

                            The proof requires:

                            ∀ 0 < y, ∃ k : X - y < pk < X

                            The case where y ≥ X - 1 is elementary:

                            ∀ y ≥ X - 1, X - y ≤ 1 < pi < X

                            So we are left with showing:

                            ∀ 0 < y < X - 1, ∃ k : X - y < pk < X

                            Thr section (0,1) seems to be easy. Since:

                            ∀ x,y > 0, b > 1 : x < y ⇔ Logb(x) < Logb(y)

                            I can take the Log base p0 [call this LP] of the inequality ( :confused: ) to get:

                            LP(X) = ln(X) / ln(X ^ (1/X)) = ln(X) / ((1/X) ln (X)) = X
                            LP pk = pk-1
                            LP(X - y) = X × [ln(X - y) / ln(X)]

                            Let α = ln(X) - ln(X - y)
                            = ln(X) - ln(X) × ln(-y)
                            = ln(X) × [1 - 1/ln(y)]

                            ∴ LP(X - y) = X × [1 - α / ln(X)]
                            = X × [1 - ln(X) × (1 - 1/ln(y)) / ln(X))
                            = X × [1 - (1 - 1/ln(y))]
                            = X / ln(y)

                            So the inequality is:

                            ∀ 0 < y < 1, ∃ k : X / ln(y) < pk-1 < X
                            ∀ 0 < y < 1, ln(y) < 0
                            ∴ X / ln(y) < 0 < pk < X

                            So any value of k satisfies the inequality for (0,1). This leaves the section [1,X-1). Since the lower bound is included, we simply need to show:

                            ∃ k : X - 1 < pk < X

                            In the case of X=2, any value of k satisfies this. Now, I just need proof for X > 2! I hope this make at least some sense, and doesn't read like the insane ramblings of a deranged lunatic! :) Cheers, Richard

                            "These people looked deep within my soul and assigned me a number based on the order in which I joined" - Homer

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