Great EXPectations

Given that x^(x^(x^(x^(x^(x^(x^(x^(x…)))…) = 2, solve for x.

Communicated by J. Goldfoot.

21 Comments

  1. Steven Miller on December 8, 2012 at 9:04 pm

    anon — yes — [email protected]



  2. Steven Miller on October 1, 2012 at 6:30 pm

    anonymous: please include name/email: correct (sjm1 AT williams.edu)



  3. Steven Miller on September 19, 2012 at 5:55 am

    Jimmy: well done (sjm1 AT williams.edu)



  4. Steven Miller on July 24, 2012 at 3:13 am

    I don’t understand: if x tends to infinity how can x tend to 1? email me at sjm1 AT williams.edu



  5. Terry on July 23, 2012 at 9:19 am

    As I’m doing this on my phone please forgive typos and lack of proper notation. As x tends toward infinity then the answer tends toward 1. So the limit of x^x^x = 2 as x tends to infinity is x tending toward 1. Isn’t it??



  6. Steven Miller on April 2, 2012 at 8:06 pm

    Your parentheses are off; if x = 1 + 1, then it is (1+1)^( (1+1)^(…) …).



  7. lol on April 2, 2012 at 8:03 pm

    no it won’t (1+1^(1+1^(1+1^(1+1…….)…) will equal 2, since 1 + 1^anything = 2.



  8. Steven Miller on April 2, 2012 at 7:47 pm

    Nope — that will give too big an answer //s



  9. lol on April 2, 2012 at 7:26 pm

    x = 1+1??



  10. Steven Miller on December 31, 2011 at 3:29 am

    Anon: you’re close but not quite there — email me at [email protected] if you want to discuss more.



  11. Anon on December 31, 2011 at 2:59 am

    let a^x = x^(x^(x^(x^…))…)
    so a^x = 2
    Take logs of both sides.
    ln(a^x) = ln(2)
    x*ln(a) = ln(2)
    x = ln(2)/ln(a)
    But since a is x to the power of x an infinite number of times, a = 2. So ln(a) = ln(2).

    Therefore x = 1.



  12. Steven Miller on December 1, 2011 at 2:01 am

    It’s not 2/3…. email me at [email protected] if you want a hint



  13. kareem on December 1, 2011 at 12:57 am

    2/3



  14. Steven Miller on November 21, 2011 at 12:27 am

    There’s a very simple solution. Email me at [email protected] if you want the soln or a hint.



  15. Some guy on November 20, 2011 at 8:23 pm

    X = ∞√2

    ^That does not say infinity times root 2. I just don’t know how to type unicode for infinity root 2 or however it’s supposed to be said



  16. Steven Miller on September 29, 2011 at 7:31 pm

    To ANT: correct!



  17. ANT on September 29, 2011 at 7:17 pm

    x=sqrt(2)



  18. Steven Miller on June 22, 2011 at 1:56 am

    Nope — if x = 2 you end up getting infinity.



  19. Prasan on June 22, 2011 at 12:17 am

    X = 2



  20. Steven Miller on June 21, 2011 at 8:47 pm

    It means the process continues. Take the limit of x, x^x, x^(x^x), x^(x^(x^x)), ….



  21. Korbin on June 21, 2011 at 6:09 pm

    what do the dots mean? can u email me and write out the whole question without simplifying it or shortening it



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