Donate Bitcoin

Donate Paypal


PeakOil is You

PeakOil is You

Amazing Mathematical Curiosity

What's on your mind?
General interest discussions, not necessarily related to depletion.

Amazing Mathematical Curiosity

Unread postby PenultimateManStanding » Wed 14 Feb 2007, 16:51:00

This comes from Hippocrates of Chios (not the doctor one) who studied lunes (moon-shaped figures created by intersection of circles) I'll describe this with modern terms: consider the unit circle and plot the points created by the intersection of rotating a ray of length one counterclockwise 90 degrees (pi/2 radians) while moving a vertical line backwards from one to zero on the x-axis. for example, if the ray is rotated 1/4 of the way to 90 degrees, the vertical line has moved 1/4 of the way from 1 to 0 (and lies at x=3/4). So plotting all of these points creates a curve beneath the quarter circle created by the ray rotating. Heres the amazing thing if you can follow the description so far: when the ray has rotated 90 degrees so the ray points up along the y-axis, the other curve crosses the y axis at 2/pi: the inverse of the radian rotation of the ray (pi/2). This point can be used to square the circle (but there's a catch in that the point is a limit)


It looks very interesting if you plot some of these points and sketch the lower curve. You can see that it crosses the y-axis at around 2/3. I calculated it using the expression for the points of intersection being: x tan[(1-x)90]
if you set x very small you get approximately 2/pi. clearly if x=0 the expression doesn't work, which is related to the fact that the circle can't actually be squared.
Last edited by PenultimateManStanding on Wed 14 Feb 2007, 17:20:15, edited 1 time in total.
User avatar
PenultimateManStanding
Expert
Expert
 
Posts: 11363
Joined: Sun 28 Nov 2004, 04:00:00
Location: Neither Here Nor There

Re: Amazing Mathematical Curiosity

Unread postby NEOPO » Wed 14 Feb 2007, 17:15:57

Image

Image
It is easier to enslave a people that wish to remain free then it is to free a people who wish to remain enslaved.
User avatar
NEOPO
Permanently Banned
 
Posts: 3588
Joined: Sun 15 May 2005, 03:00:00
Location: THE MATRIX

Re: Amazing Mathematical Curiosity

Unread postby PenultimateManStanding » Wed 14 Feb 2007, 17:35:57

the area of the lune is equal to the area of the inscribed triangle. It's not hard to see why using the pythagorean theorem and looking at the areas of the squares on the similar chords which happen to be the sides of the inscribed right isosceles triange. Hippocrates was the first to find the quadrature of a circular shape in this way.
User avatar
PenultimateManStanding
Expert
Expert
 
Posts: 11363
Joined: Sun 28 Nov 2004, 04:00:00
Location: Neither Here Nor There

Re: Amazing Mathematical Curiosity

Unread postby cynicalheretic » Wed 14 Feb 2007, 17:59:40

Dude, seriously, go smoke some damn weed.
cynicalheretic
Permanently Banned
 
Posts: 594
Joined: Thu 02 Nov 2006, 04:00:00

Re: Amazing Mathematical Curiosity

Unread postby PenultimateManStanding » Wed 14 Feb 2007, 18:12:51

$this->bbcode_second_pass_quote('cynicalheretic', 'D')ude, seriously, go smoke some damn weed.
heh heh, seriously indeed, I read about this in a book called "The History Of Pi" which I found in a teacher's desk the day before yesterday and have been pondering it for two days. I got the lune part right away, but this curve is mysterious. In fact, drawing both the circle and the intesection points looks like a lune! So today I figured it out and wanted to "share" it with my more mathematically inclined fellow members of po.com. You ought to go over to that other thread and tell us some more stories about your childhood if you don't find geometry interesting.

edit: oh, I see you did already!
User avatar
PenultimateManStanding
Expert
Expert
 
Posts: 11363
Joined: Sun 28 Nov 2004, 04:00:00
Location: Neither Here Nor There

Re: Amazing Mathematical Curiosity

Unread postby gampy » Wed 14 Feb 2007, 18:36:47

Ahhh...the joy of discovering mathematics and geometry. I remember playing with rulers and those circumscribing thingies in English class when I should have been paying attention to Shakepeare's sonnets.

To think that these fellows in antiquity discovered all this stuff for the first time! To have that "Eureka!" moment.

It is so profound to see God in a circle, square and triangle.
User avatar
gampy
Tar Sands
Tar Sands
 
Posts: 761
Joined: Fri 27 Oct 2006, 03:00:00
Location: Soviet Canada

Re: Amazing Mathematical Curiosity

Unread postby PenultimateManStanding » Wed 14 Feb 2007, 19:46:38

$this->bbcode_second_pass_quote('gampy', ' ')
It is so profound to see God in a circle, square and triangle.
yes indeed, it is mysterious, in fact. I tried the same thing with the expression x tan[(1-x)90] at the other end where x -> 1 and got a very strange result. I set x = .9, .99, .999, .9999 and got powers of ten times a number which was off from 1/2pi by about 4/100. I'm not sure what it means but it is strange. The powers of ten part is not hard to see, but the limit being off from 2pi by about 4/100 is weird. BTW, Leonardo da Vinci spent a lot of effort on the "squaring the circle" problem. It wasn't shown until 1882 that it can't be done. Obviously, some lunes can be squared, but not a circle.
User avatar
PenultimateManStanding
Expert
Expert
 
Posts: 11363
Joined: Sun 28 Nov 2004, 04:00:00
Location: Neither Here Nor There

Re: Amazing Mathematical Curiosity

Unread postby cynicalheretic » Wed 14 Feb 2007, 20:40:41

$this->bbcode_second_pass_quote('PenultimateManStanding', '')$this->bbcode_second_pass_quote('gampy', ' ')
It is so profound to see God in a circle, square and triangle.
yes indeed, it is mysterious, in fact. I tried the same thing with the expression x tan[(1-x)90] at the other end where x -> 1 and got a very strange result. I set x = .9, .99, .999, .9999 and got powers of ten times a number which was off from 1/2pi by about 4/100. I'm not sure what it means but it is strange. The powers of ten part is not hard to see, but the limit being off from 2pi by about 4/100 is weird. BTW, Leonardo da Vinci spent a lot of effort on the "squaring the circle" problem. It wasn't shown until 1882 that it can't be done. Obviously, some lunes can be squared, but not a circle.



It's amazing PMS, only you could be a big enough geek to nerd up a forum about hydrocarbon depletion
cynicalheretic
Permanently Banned
 
Posts: 594
Joined: Thu 02 Nov 2006, 04:00:00

Re: Amazing Mathematical Curiosity

Unread postby PenultimateManStanding » Wed 14 Feb 2007, 20:44:49

$this->bbcode_second_pass_quote('cynicalheretic', '[')
It's amazing PMS, only you could be a big enough geek to nerd up a forum about hydrocarbon depletion
:lol: :lol: "I'm too sexy for my shirt, too sexy for my shirt" blah blah.
User avatar
PenultimateManStanding
Expert
Expert
 
Posts: 11363
Joined: Sun 28 Nov 2004, 04:00:00
Location: Neither Here Nor There
Top

Re: Amazing Mathematical Curiosity

Unread postby MD » Wed 14 Feb 2007, 20:46:05

This is where I admit to a thrill of euphoria that lasted for three days after I learned how to calculate pi through calculus...

yup...it's true...that kind of shit reaches deep in my soul.
Stop filling dumpsters, as much as you possibly can, and everything will get better.

Just think it through.
It's not hard to do.
User avatar
MD
COB
COB
 
Posts: 4953
Joined: Mon 02 May 2005, 03:00:00
Location: On the ball

Re: Amazing Mathematical Curiosity

Unread postby PenultimateManStanding » Wed 14 Feb 2007, 20:59:16

$this->bbcode_second_pass_quote('MD', 'T')his is where I admit to a thrill of euphoria that lasted for three days after I learned how to calculate pi through calculus...

yup...it's true...that kind of shit reaches deep in my soul.
mine too, my friend, mine too. It puts where we are into perspective, if you know what I mean.
User avatar
PenultimateManStanding
Expert
Expert
 
Posts: 11363
Joined: Sun 28 Nov 2004, 04:00:00
Location: Neither Here Nor There
Top

Re: Amazing Mathematical Curiosity

Unread postby PenultimateManStanding » Wed 14 Feb 2007, 21:04:40

Archimedes was working out one of his brilliant ideas, and they were brilliant, he was the best mathematician of the ancient age, when the Romans overran Syraceus. Some ignorant soldier killed him because Archimedes was too rapt in attention to the language of the Universe.
User avatar
PenultimateManStanding
Expert
Expert
 
Posts: 11363
Joined: Sun 28 Nov 2004, 04:00:00
Location: Neither Here Nor There

Re: Amazing Mathematical Curiosity

Unread postby gampy » Wed 14 Feb 2007, 21:39:59

I am trying to remember my first mathematical epiphany.
Sorry for the religious references, but I suppose there is something of the religious in the pursuit and capture of knowledge, and understanding.

Hahaha...I remember. I was in 3rd grade I think. Our class was beginning to study fractions and the addition and subtraction thereof.
I could not grasp the concept until my family was having pizza for supper, and my mother asked how much was left, so I had to add up the slices from 3 different boxes. I still remember using that visualization when doing the quizzes. All the fractions were pizza slices, and the whole numbers were pizzas. It worked!

And getting my head around the idea of multiplying negative integers.
That was satisfying, once I fully understood.
User avatar
gampy
Tar Sands
Tar Sands
 
Posts: 761
Joined: Fri 27 Oct 2006, 03:00:00
Location: Soviet Canada

Re: Amazing Mathematical Curiosity

Unread postby PenultimateManStanding » Wed 14 Feb 2007, 22:00:08

$this->bbcode_second_pass_quote('gampy', 'I') am trying to remember my first mathematical epiphany.
Sorry for the religious references, but I suppose there is something of the religious in the pursuit and capture of knowledge, and understanding.

Hahaha...I remember. I was in 3rd grade I think. Our class was beginning to study fractions and the addition and subtraction thereof.
I could not grasp the concept until my family was having pizza for supper, and my mother asked how much was left, so I had to add up the slices from 3 different boxes. I still remember using that visualization when doing the quizzes. All the fractions were pizza slices, and the whole numbers were pizzas. It worked!

And getting my head around the idea of multiplying negative integers.
That was satisfying, once I fully understood.
thanks, gampy, I like your story. In fact, I use that analogy all the time because it makes it real. As a teacher, I'm always trying to make it real, searching for ways to make it real. I took the story of pi as I read it in that book and tried to present it in a way that could be understood. One can only try. BTW, I use debt as a way of understanding negative numbers.
User avatar
PenultimateManStanding
Expert
Expert
 
Posts: 11363
Joined: Sun 28 Nov 2004, 04:00:00
Location: Neither Here Nor There
Top

Re: Amazing Mathematical Curiosity

Unread postby gampy » Wed 14 Feb 2007, 22:31:45

$this->bbcode_second_pass_quote('PenultimateManStanding', '')$this->bbcode_second_pass_quote('gampy', 'I') am trying to remember my first mathematical epiphany.
Sorry for the religious references, but I suppose there is something of the religious in the pursuit and capture of knowledge, and understanding.

Hahaha...I remember. I was in 3rd grade I think. Our class was beginning to study fractions and the addition and subtraction thereof.
I could not grasp the concept until my family was having pizza for supper, and my mother asked how much was left, so I had to add up the slices from 3 different boxes. I still remember using that visualization when doing the quizzes. All the fractions were pizza slices, and the whole numbers were pizzas. It worked!

And getting my head around the idea of multiplying negative integers.
That was satisfying, once I fully understood.
thanks, gampy, I like your story. In fact, I use that analogy all the time because it makes it real. As a teacher, I'm always trying to make it real, searching for ways to make it real. I took the story of pi as I read it in that book and tried to present it in a way that could be understood. One can only try. BTW, I use debt as a way of understanding negative numbers.


I think a lot of kids (and adults) have difficulties with mathematics because of the language, the syntax, the symbols used. I think if you have an affinity for languages, you probably have an affinity for mathematics, as it is taught today and in the past.

I think it's been shown that the human mind learns best by doing. Tactile sensation has a huge impact on learning and cognition.
I remember taking a geology course in high school. Most kids think geology is a dry, dull subject. I guess it is if you teach it from a blackboard and a textbook. My teacher would bring in all his rocks and samples and occasionally would take the class out and have us actually walk on, and touch, and see the rock formations and strata he would talk about in class. To this day I can remember his class better than any other class I had that year. I also retained the information presented so much better.

I think it's possible to do that with mathematics as well. I guess it takes a love of math and some creativity to present ideas that people can readily pick up on and apply. It must be fascinating for you to see some of your students have that "Eureka!" moment. To see the look on their face as they grasp a strange concept.

Lol. I remember the frustration on a math teacher's face when after presenting the concept of multiplying and dividing negative integers
the class just kind of looked around at each other with puzzled expressions on their faces. I have the feeling that a lot of students hate math because they were round pegs rammed into a square hole. If you could not get the idea, you failed. When it's the teacher who fails.
User avatar
gampy
Tar Sands
Tar Sands
 
Posts: 761
Joined: Fri 27 Oct 2006, 03:00:00
Location: Soviet Canada
Top

Re: Amazing Mathematical Curiosity

Unread postby cynicalheretic » Wed 14 Feb 2007, 22:33:58

You broke the 8000 post barrier... congratulations are in order I guess. Or pity is due, I am not sure which :P
Last edited by cynicalheretic on Wed 14 Feb 2007, 22:42:59, edited 1 time in total.
cynicalheretic
Permanently Banned
 
Posts: 594
Joined: Thu 02 Nov 2006, 04:00:00

Re: Amazing Mathematical Curiosity

Unread postby PenultimateManStanding » Wed 14 Feb 2007, 22:39:22

I recall that studies show only 5% of people are able to understand what is expected that teachers are supposed to show all young students for comprehension about mathematics. It's absurd. This is why I chose to be a sub. I won't be captured by an existential absurdity.
User avatar
PenultimateManStanding
Expert
Expert
 
Posts: 11363
Joined: Sun 28 Nov 2004, 04:00:00
Location: Neither Here Nor There

Re: Amazing Mathematical Curiosity

Unread postby cynicalheretic » Wed 14 Feb 2007, 22:47:01

In highschool I understand everything my teachers talked about. College on the other hand, what the fuck am I doing studying about petrology from a guy who believes that Oil is abiotic.
cynicalheretic
Permanently Banned
 
Posts: 594
Joined: Thu 02 Nov 2006, 04:00:00

Re: Amazing Mathematical Curiosity

Unread postby peaker_2005 » Thu 15 Feb 2007, 03:33:12

$this->bbcode_second_pass_quote('cynicalheretic', 'I')n highschool I understand everything my teachers talked about. College on the other hand, what the fuck am I doing studying about petrology from a guy who believes that Oil is abiotic.


:lol:
"Human beings, who are almost unique in having the ability to learn from the experience of others, are also remarkable for their apparent disinclination to do so." - Douglas Adams
User avatar
peaker_2005
Tar Sands
Tar Sands
 
Posts: 686
Joined: Fri 02 Sep 2005, 03:00:00
Top

Re: Amazing Mathematical Curiosity

Unread postby MD » Thu 15 Feb 2007, 07:09:13

An early mathematical epiphany of mine occured when I was bouncing a ball and realized that "hey, if it rebounds to a fraction of it's height each time, then it should bounce forever". I then spent quite a while counting bounces. The "superballs" were the best. The original black ones that came in various sizes were my favorites.

To this day I'd like to try it in a vacuum with various materials. I bet you could get bounce counts in the thousands. The tail-off curves would be immensely interesting, I'm sure.

Surely some school science class has done this . . . time for a quick google.
Stop filling dumpsters, as much as you possibly can, and everything will get better.

Just think it through.
It's not hard to do.
User avatar
MD
COB
COB
 
Posts: 4953
Joined: Mon 02 May 2005, 03:00:00
Location: On the ball

Next

Return to Open Topic Discussion

Who is online

Users browsing this forum: No registered users and 3 guests