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pi

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Thread replies: 36
Thread images: 4

File: shiiiiit.jpg (43KB, 425x600px) Image search: [Google]
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So I was in a thread on /b/ and saw pic related. My question is if it is true. (please provide evidence to support your answer)
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Thats math breaking
>>
This has been beaten to death here, but yes, I think it is true.

The problem is that it isn't the perimeter of a circle, after infinite iteration this shape contains infinitesimal edges that all add up to made a perimeter of 4.

Sorry if this explanation sucks. I'm tired.
>>
Pi is the ratio of the circumference of the circle to its diameter.
The perimeter is not the same as the circumference!
The circumference is the perimeter of a circle, not a square.
Circumference is equal to 2piR
where R is the radius, or half the diameter.

a fucking school child could tell you this.
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By definition it cannot be a circle due to the fact that it is made up of ininite line segments.
>>
>to infinity
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>>8480543

only for large values of pi
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>>8480543
The line of a circle in a world of reals does not have bumps.

The line produced by that limit has bumps of infinitisimal length.

The resulting perimeter is actually pi + a sum of infinitely many infinitesimal bumps. How much does this sum equal? Easy. 4 - pi.
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>>8480543
It's true, pi < 4
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>>8480543
if you do that you have an infinite amount of tiny bumps that add to the perimeter/circumference which adds an infinite amount of shit to the perimeter. I could say that the perimeter is 5 billion if you get enough bumps.
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>>8480587
This was never funny
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Limits are to actual values as undefined is to defined.
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https://youtu.be/CMP9a2J4Bqw
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>>8480673
Not related.
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>>8480543
this is like saying that it is the same to go from california to Florida and then to new York, than going straight from California to NY, knowamsayin
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>>8480543
>repeat to infinity
define it and explain the process

mathematics with vague notions will always result in vague, if not incorrect, results
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>>8480543
> pi = 24
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>>8480568
But that's exactly what a circle is
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1)
Induction only works for a finite number of steps. You cannot induct to show that the infinite case hold true. For example, you cannot induct on the rationality of 3, 3.1, 3.14, etc. to show that pi is rational.

2) induction aside, the resultant figure is not a circle. A circle contain uncountably many points along it's perimeter, whereas that figure contains countable many points on the perimeter (each point touching the meme circle was bent at some finite step in the process, and each step adds in a finite number of points) at which it was
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>>8480784
the black lines are an incredibly poorly drawn picture of a circle made up of a bunch of line segments
the red lines are what the method in OP gives
You will note that the red lines have a larger perimeter than the black lines

>>8480784
have you ever looked up the definition of a circle?
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File: circle.png (6KB, 827x924px) Image search: [Google]
circle.png
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>>8480784
forgot pic
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>>8480553
but it approximates the circumference of a circle
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>>8480543
TOC tic board missing a line. Xxx
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>>8480543

mimicked shapes do not necessarily share more attributes (with an original) but the mimicked shape. also, two same sized catheti will always be longer than the corresponding hypotenuse - no matter how "infinite small" the triangle gets.
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File: pi is an algebraic number.png (19KB, 750x776px) Image search: [Google]
pi is an algebraic number.png
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4 is the wrong answer
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>>8480828
A circle is just one dot with a bunch of lines / vectors coming from it with the same R
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>>8480543
>entire thread is brainlets whining about limits and infinity
this is NOT the problem. the problem is the assumption that just because you have a sequence of curves f_n that converges to some curve f, THIS DOES NOT IMPLY that the arclengths of the f_ns converge to the arclength of f.

inb4 angry 10 year old who dont know the definition of arclength disagree with me

theres a better version of that picture, btw: take a square and indent one corner inside, repeat for smaller corners etc and you get 2 = sqrt(2)
it's better because it's simpler
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>>8480989
The area, not the perimeter.
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>>8480553
>after infinite iteration this shape contains infinitesimal edges that all add up to made a perimeter of 4.
that was so dumb I think it gave me cancer. the given sequence of curves converges (uniformly even) to the circle.

tell me what you dont understand about this and we'll have a talk
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>>8480543
Congratulations, you've determined the circumference of that weird shape in the taxicab metric
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This would be so easy to explain with Landau symbols. Why does nobody use Landau symbols?
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>>8481528
use them and explain, then
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I don't understand what this math thing is. Like... why math?
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File: spiukes.png (10KB, 601x811px) Image search: [Google]
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>>8480543
Here's an explanation, brainlets.
Imagine a different example, where instead you placed points around a circle and made tiny tiny triangles with roughly negligible area. You then take these triangles, and stretch them out far away from the circumference of the circle, but at the same time adjust the closeness of the base points such that the area of the triangles remains constant as they stretch out (similar to the dirac delta function). You would end up with a shape that has a massive perimeter, but almost identical area to before. This is why this doesn't work. Pi is by definition, the ratio of circumference to diameter for a circle. This is not a circle.
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You have a sequence of paths [math]\gamma_n(t)[/math] representing the perimeter with each time corners removed. E.g [math]\gamma_1(t)[/math] is a square and [math]\gamma_2(t)[/math] and [math]\gamma_3(t)[/math] represents the perimeters as in the pictures 3 and 4. Now for each natural number [math]n[/math], the length of [math]\gamma_n(t)[/math] is [math]\int_0^1|\gamma_n'(t)| dt=4[/math]. But if we let [math]n[/math] approach to infinity, we get a circle [math]\gamma_(t)[/math] which lenght is [math]\int_0^1|\gamma'(t)| dt=\pi[/math].


so in this case [math] \lim_{n \rightarrow \infty} \int_0^1 |\gamma_n'(t)|dt= 4 \neq \int_0^1 |\frac{d}{dt} \lim_{n \rightarrow \infty} \gamma_n(t)|dt=\pi[/math]
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>>8481281
Correct answer.
Thread posts: 36
Thread images: 4


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