The Math Problems Thread :D

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miyano_shiho
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Re: The Math Problems Thread :D

Post by miyano_shiho »

Akonyl wrote: not to mention, you define ((x))3 as x^x^x, which means that ((x))2 would be x^x, which means that ((x))1 is just x, in which case, how is ((0))1 == 1? I could see maybe if you meant ((0))0 though, or if you improperly defined ((x))3 as x^x^x.
I noticed that too. I think it was probably just a typo. I mean, she really meant to write ((0))1 = 0 and ((0))2 = 1 but apparently interchanged them. (Mathematicians make those kind of mistakes too... ^^)
Akonyl wrote: also, I'm not sure what you mean by "Try 1.1, or 0.1", because those seem to fit the assumption of "1.1 goes to +inf, and 0.1 converges" that you said they break, so  :-X
While 0.1 seems to converge, 1.1 does not actually go to +inf, it actually converges and this becomes apparent once you reach the 10th iteration. The 7th to 11th values are: 1.111781994, 1.111782009, 1.11782011, 1.11782011, 1.11782011(They aren't the same, the calculator just can't display further decimal places anymore.)

From what I have noticed, the closer the value of x to 0, the more the values seem to oscillate uniformly.
At x=0.01: 0.01, 0.95, 0.01, 0.94, 0.01, 0.94 (and it seems to diverge).

Actually, 0.1 seems to oscillate at first but it dampens since it is convergent. (The first 10 values are (in two decimal places): 0.10, 0.79, 0.16, 0.69, 0.20, 0.63, 0.24, 0.58, 0.26, 0.55)

The closer the value of x to 1, the less it oscillates and it dampens faster (or the less the differences between the odd and even iterations. For example, at x=0.5: 0.50, 0.71, 0.61, 0.65, 0.64, 0.64.

At higher values, the more apparent that it diverges.

Also, according to the wiki article that you posted,
Wikipedia wrote:In general, the infinite power tower, defined as the limit of nx as n goes to infinity, converges for e−e ≤ x ≤ e1/e, roughly the interval from 0.066 to 1.44, a result shown by Leonhard Euler.
  ;D

That sums up my observations. But I'm still looking forward to what Giogio has to say, and yes, the proof.  ;)

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Re: The Math Problems Thread :D

Post by Akonyl »

yeah, I didn't browse the page I posted completely, but that makes sense. I was just assuming from the speed it increased that it was divergent rather than convergent. Was still right about 0.1, though :P
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Re: The Math Problems Thread :D

Post by shubhoshinichi »

Sorry, @ Miyano.. From now on i'm gonna be regular. So, starting with a simpler problem...

I have a few sweets to be distributed. If i keep 2, 3 and 4 in a pack, I'm left with one sweet. If i keep 5 in a pack, I'm left with none. What is the minimum no. of sweets I can have to pack and distribute?
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miyano_shiho
I just love numbers... :)

Posts:
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Re: The Math Problems Thread :D

Post by miyano_shiho »

@Shubho: It's okay. Even I don't have much time to post here (I'm getting busier and busier)...
Spoiler: Answer
13
The problem may be solved by simple trial and error (that's what I actually did  ;))
...but there's actually a theorem for solving problems involving remainders and it's called the "Chinese remainder theorem", which involves modular arithmetic.

I'll save the solution for Shubho or for others who might want to solve it (or present a similar problem). :D


I will post about the Chinese remainder theorem and other famous theorems in number theory some time... ;D

“Friendship is like standing on wet cement. The longer you stay, the harder it's to leave, and you can never go without leaving your footprints behind.” - Unknown

“If you don't go after what you want, you'll never have it. If you don't ask, the answer is always no. If you don't step forward, you're always in the same place.” - Nora Roberts

"Enjoy the little things in life, for one day you may look back and realize they were the big things." - Robert Brault

"Time is an equal opportunity employer. Each human being has exactly the same number of hours and minutes every day. Rich people can't buy more hours. Scientists can't invent new minutes. And you can't save time to spend it on another day. Even so, time is amazingly fair and forgiving. No matter how much time you've wasted in the past, you still have an entire tomorrow." - Denis Waitley
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