. . . x
If x is any positive real number, then what is the value of the infinitely nested radical expression above?
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I have a question. If x can be any positive real number, suppose x is 65,536. Isn't the square root of the square root of the square root of 65,536 two? I've never taken calculus.
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Here the root goes n times.. It's not just 4 square roots..
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Thanks for clearing this up for me Amalnath. I wondered what those little dots before the x meant!
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@Solomon Barrow – @Solomon Barrow thanks for respecting an Indian, m saying this as everywhere else people especially from the west show no respect for a fellow human being; & I have proofs
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@Sumit Kr Mishra – Thanks Sumit. I try to treat everyone with respect, regardless where they come from or their station in life. You should be especially proud to be from India. One of the greatest mathematician of all time was from your country, and I'm quite certain you know of whom I speak. Stay brilliant kid!
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@Solomon Barrow – @Solomon - thank u sir :)... I am really proud of my country and humanity as a whole & yeah he is Ramanujan, many more Aryabhatta, Varahmihir, are also there... bdw recently I had tried asking a question about why is India backward although this was the country where people devised the modern number system all use, was once the richest country as per a non Indian( Angus Maddison).... the people started abusing Indians, Paksistan, and most of all what made me angry was they say India gave nothing to the world, the arabs devised it... its not a fact but half fact
The square is not limited to three or four times. Its infinite square root. So when u apply square root continuously it will at one point give u ghe answer as 1 and whose square root is alway 1 inspite of the numberof time u apply ssquare root on it.
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Thanks Arun. I will try to remember that!
Actually, Arun, the answer will only ever approach 1, asymptotically. That implies that the square root will have to be applied an infinite number of times to get "1". Understanding that, one does not even have to calculate anything to get the answer.
what if the number is between 0 and 1 i.e a fraction ?
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whatever x positive real number , $x^{\frac{1}{2^{n}}}===>1$
Take 0.2 (2/10 or 1/5, when reduced) as an example. The square root of 0.2 is approximately 0.447; the square root of that is approximately 0.669; the square root of that is approximately 0.818, and so on. The sequence approaches one, asymptotically. Use a calculator with a square root function to see this for yourself; it's kind of cool to watch :)
Peefect! But, didn't the problema ask for the radical rather than the solution itself!?
Does the "n" only apply to the two or the one as well? If it does apply to the one, they why? If only the two then why as well? In other words, how did you get x^o
The only problem with the answer being 1 is that 1 squared = 1. Finding square roots of real numbers or positive numbers like 16 =4 and so on.
A misleading and dubious branch of mathematics I would say.
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It's actually correct, wacky though it may seem. When you go on to infinities, your results are very weird. Take the infinite series 1 + 1/2 + 1/4 + 1/8... going on to infinity. You can use algebra to prove that it adds up to 2. If you call the series x, then 2x is 2 + 1 + 1/2 + 1/4 + 1/8..., which is the same as 2 + x, so x is 2, even though it seems really wacky.
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Thanks Alex, I thought I had taken leave of my senses.
I have been thinking on how the number 1 comes into being. In geometric terms that is Euclidean terms. We have a point designated as 0 and then from there to 1. and 2 etc. I presume this a one dimensional drawing. In the physical world we have at least three dimensions + time. So I would conclude that 1 is a space in three dimensions, the 0 being a point without space.
I would like to write more on the generation of numbers using geometry of at least two dimensions. Compass and straight edge style.
let a > 0 such that . . . x = a
. . . x 2 = a 2
. . . x = a 2
a = a 2
The equation, a 2 − a = 0 , has 0 and 1 as roots.
But since a > 0, therefore a = 1.
How do you know that the limit exists without e.g. Monotonicity and boundedness?
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limit is for n not x and domin for x no need to think about monotonocity
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I beg to differ. You don't know whether the limit exists until you prove it does. The easiest way is to prove that the sequence is increasing for x less than 1 and decreasing for x bigger than 1, and that in either case the bound (upper and lower resp.) is 1
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@Roberto Vilarrubi – The limit does not exist!!!!
It is also possible that the limit is 0, even if all the terms of the sequence are positive. One example will be successive squares (instead of square roots). The limit can be 0 for starting positive numbers below 1 and infinity for numbers above 1 ( and 1 when you start from 1)
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Once again they post a question without enough information. This question needs a x>1 or 0<x<1 as each yields a different answer.
Used the same technique ;)
it helps......buddy. tnx
Splendid !
This is exactly what I did.
Basically, if you continuously square root any number, you tend to 1. Square root X = X^0.5 (square root of that = X^0.25, and so on....) X^0.5, X^0.25, X^0.125......tending towards X^0 which is 1
I used a similar line of thinking to solve it.
...√√√√√√...x can be written as (((((x^½ )^½ )^½ )^½ )^½ ...).
It can be simplified into:
(((((x^½ )^½ )^½ )^½ )^½ ...) = lim n -> ∞ (x^(1/(2^n))).
lim n -> ∞ (x^(1/(2^n))) = x^(1/∞) = x^0 = 1. Thus, 1 is the answer.
OR
Let ...√√√√√√...x = y
y² = ...√√√√√...x
But, ...√√√√√√...x = y
Thus, y²-y = 0, or y(y-1) = 0.
y = 0 or y = 1. But y = 0 cannot be the answer because,
lim n -> ∞ (x^(1/(2^n))) = 0 means that; x^0 = 0 or 1 = 0. IMPOSSIBLE!!!
Thus, 1 is the answer!
Easy trick: the problem asks for solution where x is ANY positive number. Just choose x = 1, the result is surely 1.
I thought i was the only one, I felt so weird... Anyway the a^2+a=0 one is pretty elegant, I have to say.
What if x = 2?
it's 1. Try it out on a calculator.
I found that this was able to be put into a simple formula
x=√(x)
(We substitute that function into "x" infinitely.)
Therefore, we would get
(X^2)=x
Which then can become a quadratic
(X^2)-x=0
We know that the roots of the quadratic are 1 and 0, but since it cannot be zero, it is One.
(This system can easily be used anywhere in any infinite summation, fraction, subtraction, or product. )
Let vvv.....x=S S²=S S=1
*vx:root x
Let us consider a positive number 'x' less than one first. Sq root of 'x' will be a number greater than itself but not equal to 1. But on repeating sq rooting the value will come closer to one and finally become one. After the value becomes 1 further sq rooting means nothing. Similarly let 'x' be a number greater than 1. Sq root of 'x' will be smaller than 'x' but not equal to 1. But repeated sq rooting will eventually provide us with 1.
If x is any positive real number, then just say that x is 1. Therefore, the value of the expression is 1.
Let X be any positive real number and taking root n times, i.e. (X)^(1/n), now as n tends to infinity , 1/n tends to 0 Hence (X)^0 =1.
The issue I had here and chose 0 was, if x <1 then the limit would go to zero wouldn't it? So if we infinitly rooted .5, which is a positive real number, wouldn't we end at 0?
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That was exactly my thinking as well.
No it actually still goes to 1. The square roots for numbers greater than zero and less than one get progressively larger and asymptotically approach 1. You never quite reach one, however, unless the square root is actually applied infinitely many times. That's why we take the limit of x^(1/n) as n goes to infinity. Then you have x^0 and we all know any number x within the bounds of this problem raised to the zeroth power will be exactly 1.
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Relevant wiki: Nested Functions
An infinite number of square roots are applied on x so we have ⋯ ⋯ x = ( ( ( x 1 / 2 ) 1 / 2 ) 1 / 2 ) ⋯ = n → ∞ lim x 1 / 2 n = x 0 = 1 .