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Subject: "Closed curve"     Previous Topic | Next Topic
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Conferences The CTK Exchange College math Topic #510
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Ganitopasak
guest
May-11-05, 10:21 AM (EST)
 
"Closed curve"
 
   What is the criteria to decide a curve is

1) Closed

2) Non-self intersecting?

Thanks for any help
====


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alexb
Charter Member
1523 posts
May-11-05, 10:22 AM (EST)
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1. "RE: Closed curve"
In response to message #0
 
   >What is the criteria to decide a curve is

What do you mean by critera?

If any exists, it may depend on how your curve is defined. In what form do you have a curve?


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Ganitopasak
guest
May-12-05, 10:38 AM (EST)
 
2. "RE: Closed curve"
In response to message #1
 
   I mean, given an equation of a curve, how do you mathematically find out if it is closed and non-intersecvting?


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sfwc
Member since Jun-19-03
May-12-05, 01:23 PM (EST)
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3. "RE: Closed curve"
In response to message #2
 
   Is the equation parametric (for example, x = sin(t), y = cos(t)) or is the curve instead specified as the solution set of an equation (for example x^2 + y^2 = 1). Or is it given in a different form again?

In the parametric case, suppose the curve (x(t), y(t)) is specified on some interval . Then the curve is closed iff x(a) = x(b) and y(a) = y(b) and non-intersecting iff for s and t in In the solution set case, the curve is usually closed if it is bounded. It is almost certainly nonintersecting if the defining function (in the above case x^2 + y^2 - 1) has nondegenrate derivative on the curve, but it is harder to give an all inclusive condition.

Thankyou

sfwc
<><


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