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-Demosthenes-

Spheres, how many sides??

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Hmm - it probably is simple we just haven't managed to work out the universal rules yet ;)

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yes thats what i'd like to know...is the original post refereing

to sides as 1) EDGES 2) SURFACES?

 

solid sphere has no edge but one surface

triangle has 3 edges and 2 surfaces

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lets see---infinte I'd say---seeing how a sphere is composed of an inf. amount of inf. small corners---but that just might be perception---hmmmm---I could see how its none---but that would mean also mean a cone has one side---how many sides does a cone have anyways?---Oh well---

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-Demosthenes- said in post # :

How many sides does a shpere have? One or infinite?

 

2--An inside and an outside. :D

 

Seriously, there's more to that answer than a joke, because in 3D analytic geometry, we aren't so much interested in the number of sides of a polygon, or the limit in which an n-gon becomes a circle, as we are in the number of ways in which a surface is orientable. In the case of the sphere, we can orient it in 2 ways. One in which the normal vectors point outwards, and another in which they point inwards.

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Tom said in post #33 :

 

2--An inside and an outside. :D

 

Seriously, there's more to that answer than a joke, because in 3D analytic geometry, we aren't so much interested in the number of sides of a polygon, or the limit in which an n-gon becomes a circle, as we are in the number of ways in which a surface is orientable. In the case of the sphere, we can orient it in 2 ways. One in which the normal vectors point outwards, and another in which they point inwards.

 

I guess you were right http://mathforum.org/library/drmath/view/57835.html

I googled it.

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http://mathworld.wolfram.com/MoebiusStrip.html

 

http://astronomy.swin.edu.au/~pbourke/surfaces/mobius/

 

http://www.chessvariants.com/shape.dir/x_moeb.html

 

 

Wow, sorry if this post doesn't seem relevant to u but some one said something about a Moebius Strip. Shame never heard of it before :-( . I mean we all must have made this like a billion times before. Try making a Moebius Strip and cut it along the middle line. It's interesting. Try the links. Absolutely no idea about the math though.

 

Don't quite see how a sphere can have infinite number of surfaces. And the concept of having zero surfaces is somewhat confusing too. I mean I see a sphere with two surfaces only.

 

 

 

Sayonara said in post 7 :

 

A side is an extrusion between two vertices.

 

A sphere has no vertices.

 

Therefore: Zero.

 

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a Sphere has 2 sides.

and inside and an outside, simple enough really :)

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"Inside" and "outside" aren't geometric sides. They're better described as within and without.

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in that case then, it has 1 side, measured in 720 degress as a ref.

angular shapes have clearly defined faces, any edge may then be taken as a Grid reference (depending on the resolution of accuracy required :)

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atinymonkey said in post # :

Depends on your definition of a side. Oh look, we are in a conversation loop. How fun.

That's because people keep posting to this thread without reading what has gone before, and some of them are reading it all but not too closely.

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or, some people believe that a circle is simply a polygon of infinite sides, so a sphere being the three dimensional representation of a circle could be a polygon of infinite sides and vertices. but i dont really care, so long as it still works the same.

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i would have said a sphere has infinite sides, probably because you can think of a sphere as a limiting form of a regular poly-oid( i dont know the correct terminology, just taken off from cub-oid).

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Like I said to Iglak, surely that would not be a sphere, but an infinitely tightly-packed mesh?

 

(edit - I am of course assuming infinite sides == infinite boundaries)

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i think u should go into a branch of mathematics called topology :)

 

for topologists i think a sphere can have as many sides as they want cos it can be deformed into any shape. (square, Pyramid .etc)

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I thought the mathematical definition of a sphere was "a continuous closed surface each part of which is equidistant from a central point".

 

If one is to ascribe infinite sides to a sphere, why not correct people who claim a cube has 6 sides and tell them that it is infinite? It seems a bit random to me.

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Like I said to Iglak' date=' surely that would not be a sphere, but an infinitely tightly-packed mesh?

 

(edit - I am of course assuming infinite sides == infinite boundaries)[/quote']

 

ok . i may be wrong . a sphere can't have infinite sides. cos infinte isnt a real number. its like saying something has 3+2i sides.

 

but on the sphere being a limiting form of a regular poly-oid.

 

while each of the members of the set . is a mesh like u said. the limit isn't

 

take for example xn=1/n.

 

the limit of 1/n as n gets large is 0 but 0 isnt in the set of {xn:n belongs to N}

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a sphere has two surfaces. the surface where the normal points towards the centre of the sphere and the surface where the normal points away from it.

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There should just be another word in the english language that is capable to describe a shere without having to wonder how many sides it has.

Since, if we dont get a genious around here well never figure out the answer that is 100% right.

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I would say spheres have 1 side

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There should just be another word in the english language that is capable to describe a shere without having to wonder how many sides it has.

Since' date=' if we dont get a genious around here well never figure out the answer that is 100% right.[/quote']

"Spherical" (see reply #42) does the job perfectly well, doesn't it?

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