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Author Topic: How many sides has a circle?  (Read 6022 times)



Well, if you're thinking about sides as in sides of a polygon, than the question doesn't really make sense since a circle isn't a polygon. Even if you wanted to say that a circle is a polygon, infinity wouldn't work either since a polygon must have a finite number of sides by definition.
I did find an interesting answer to this question here, though. He basically defines an "edge" to be a smooth curve bounded by two sharp vertices, which is nice because it works for both normal polygons and shapes with curved edges. In that case, a circle would have one edge. Honestly, it just depends on your definitions. This one makes to most sense to me, though.

Well, if you're thinking about sides as in sides of a polygon, than the question doesn't really make sense since a circle isn't a polygon. Even if you wanted to say that a circle is a polygon, infinity wouldn't work either since a polygon must have a finite number of sides by definition.
Just because a perfect circle isn't a polygon doesn't mean we can't use a limit to get the answer I got.
That's the entire POINT of limits: To find values which you can't normally reach, to get values that might be outside of the domain of what you're dealing with.

For example, the value of (x^2-1)/(x-1) is not defined at x=1. It simply does not exist. You cannot say it has a value at one at all, that's simply the definition of the equation. However, you can use a limit to still get an answer of 1.

Well, if you're thinking about sides as in sides of a polygon, than the question doesn't really make sense since a circle isn't a polygon. Even if you wanted to say that a circle is a polygon, infinity wouldn't work either since a polygon must have a finite number of sides by definition.
I did find an interesting answer to this question here, though. He basically defines an "edge" to be a smooth curve bounded by two sharp vertices, which is nice because it works for both normal polygons and shapes with curved edges. In that case, a circle would have one edge. Honestly, it just depends on your definitions. This one makes to most sense to me, though.
Just gonna point out that edge is not necessarily synonymous with side. In terms of sides, that definition doesn't work. In mathematical terms, that's just an arc. ;)

Just gonna point out that edge is not necessarily synonymous with side. In terms of sides, that definition doesn't work. In mathematical terms, that's just an arc. ;)
A bit of googling only yields precise definitions for a side in the context of polygons, so I don't really see any reason to insist that we apply that definition to something that isn't a polygon.

Just because a perfect circle isn't a polygon doesn't mean we can't use a limit to get the answer I got.
That's the entire POINT of limits: To find values which you can't normally reach, to get values that might be outside of the domain of what you're dealing with.

For example, the value of (x^2-1)/(x-1) is not defined at x=1. It simply does not exist. You cannot say it has a value at one at all, that's simply the definition of the equation. However, you can use a limit to still get an answer of 1.
A limit is one way of going about it, but referencing that second link I posted up there, it's flawed in that it doesn't distinguish between figures that we'd like to say have different numbers of sides, such as a circle, a semicircle, and this thing:

If we tried to figure out the number of sides of that thing using a limit, we'd just get infinity, the same as a circle.

A bit of googling only yields precise definitions for a side in the context of polygons, so I don't really see any reason to insist that we apply that definition to something that isn't a polygon.
All I was really saying was that an edge is not necessarily straight, whereas a side is expected to be, that's all.

All I was really saying was that an edge is not necessarily straight, whereas a side is expected to be, that's all.
Oh, sorry if I misinterpreted your post. If we require that a side be straight, then I guess you would have to say it's infinity. Again, though, I don't think it would really make sense to talk about curved figures in terms of "sides" in that case.

Oh, sorry if I misinterpreted your post. If we require that a side be straight, then I guess you would have to say it's infinity. Again, though, I don't think it would really make sense to talk about curved figures in terms of "sides" in that case.
Yeah. And if you think about it, it only makes sense that a side would have to be straight. Otherwise, where do we say it stops? If the curve continues going, then eventually it will be on the other side of itself. Just some stuff to chew on. I'm having fun thinking about all of this, actually. :P

Yeah. And if you think about it, it only makes sense that a side would have to be straight. Otherwise, where do we say it stops? If the curve continues going, then eventually it will be on the other side of itself. Just some stuff to chew on. I'm having fun thinking about all of this, actually. :P
We could say that it ends at a vertex, in which case the number of vertices on a figure would conveniently be equal to the number of sides on the figure, except when it has zero vertices. Here's a neat shape to think about:

We could say that it ends at a vertex, in which case the number of vertices on a figure would conveniently be equal to the number of sides on the figure, except when it has zero vertices. Here's a neat shape to think about:

So now the question is... Does this shape have 3 vertices and 2 sides, 3 vertices and 3 sides, or 3 vertices and infinity+2 sides?

infinity+2
infinity isn't a number silly you can't have infinity + 2

an atom's area of influence is spherical

therefore, flat physical sides are technically an illusion


infinity isn't a number silly you can't have infinity + 2

Code: [Select]
infinity = raw_input()
if infinity==2:
   print("ipquarx is gay")