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There's a theorem that states that a tangent line to any point on the cycloid passes through a point, which can be defined in terms of t, located at the top of its corresponding rolling circle. I was told that this is Descartes' theorem, but it doesn't appear to be. Thus far, I've been unable to find any record of the theorem online. Has anyone heard of it? -- Ketsuekigata 19:06, 8 May 2007 (UTC)
Don't know whose theorem it is but it follows directly from that the tangent to the cycloid must be perpendicular to the point about which the circle is instantaneously turning - therefore you get a right angled triangle in the circle with one point at the bottom and the other at the top. This can be used via Visual Calculus to get the area of the cycloid easily. Dmcq 10:31, 24 June 2007 (UTC)
Are there any excamples of cycloids in nature or engineering?
When a charged particle is subject under orthogonal electric and magnetic field, its trajectory becomes a cycloid. HotBallah ( talk) 18:49, 14 February 2023 (UTC)
Quoting Article: The cycloid through the origin, generated by a circle of radius r, consists of the points (x, y) with
x = r(t - \sin t)\,
y = r(1 - \cos t)\,
where t is a real parameter, corresponding to the angle through which the rolling circle has rotated, measured in radians (not degrees). For given t, the circle's centre lies at x = rt, y = r.
--- It would seem that you could use degrees, as long as you made 0 < t < 360. The statement that t is measured in degrees is dubious, unless there is a statement saying 0 < t < 2*pi.
Am I missing something? jheiv ( talk) 16:37, 5 May 2009 (UTC)
--Im sorry if im not writing this right, its new to me writing in wiki. the equation that written there for x by not using t isn't right, the right form of the equation is: -sqrt((2 y)/a-y^2/a^2)+cos^(-1)(1-y/a) while a=r. fix it please, I almost got wrong in work for my proffesor. — Preceding unsigned comment added by 85.250.64.229 ( talk) 16:06, 7 June 2012 (UTC)
An editor put in an edit comment saying it was differentiable everywhere, see any textbook. Could they find a citation first please for things like that which manifestly contradict what one can see. Dmcq ( talk)
Oh, sorry, I didn't see this comment. Cycloids are only ever mentioned in math books in relation to parametrized curves. They are in a sense a "classic" parametrized curve. Textbooks never even mention the Cartesian equation because it's unnecessarily complicated. "Regular" curves and "singular points" are elementary properties of differential geometry. See, e.g., Manfredo do Carmo, "Differential Geometry of Curves and Surfaces." (Cycloids are mentioned on page 7, where it says they have singular points at 2pi.)
As for derivations, I did only include the important points. No normal reader of wikipedia is going to know the trig identity that gets you to sin (t/2)--most probably won't even know the substitution rule. And clearly most are not advanced enough to know differential geometry! —Preceding unsigned comment added by 71.185.2.144 ( talk) 01:11, 22 January 2010 (UTC)
But why am I discussing this with you? Go ahead and leave this page as it was, with the claim that cycloids are not differentiable at 2n*pi. I'm moving the discussion to vandalpedia.org, where they appreciate the absurdity of wikipedia. —Preceding unsigned comment added by 71.185.2.144 ( talk) 11:02, 22 January 2010 (UTC)
hey I've seen the cycloid pendulum somewhere and i would like to give an illustration. http://commons.wikimedia.org/wiki/File:Cycloid_pendulum.png But I don't know how to use svg editors.
I hope someone can help to create an svg image or make a thumbnail of my image and then add it to the related part. —Preceding unsigned comment added by Kimkim0513 ( talk • contribs) 12:19, 20 February 2010 (UTC)
The cycloid has been called "The Helen of Geometers" as it caused frequent quarrels among 17th-century mathematicians.
This is a teaser and the reference to a text book doesn't enlighten. What quarrels? Who called it Helen? And who, for that matter, is Helen (for those who don't know their Greek mythology)? — Preceding unsigned comment added by 92.25.9.36 ( talk) 07:31, 30 April 2013 (UTC)
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It seems like we could profitably cut several sentences about speculative attributions that were later shown to be wrong. This might be in scope for some deep dive or historiography study, but doesn't really seem that helpful to readers of this encyclopedia article. – jacobolus (t) 07:32, 1 April 2023 (UTC)
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There's a theorem that states that a tangent line to any point on the cycloid passes through a point, which can be defined in terms of t, located at the top of its corresponding rolling circle. I was told that this is Descartes' theorem, but it doesn't appear to be. Thus far, I've been unable to find any record of the theorem online. Has anyone heard of it? -- Ketsuekigata 19:06, 8 May 2007 (UTC)
Don't know whose theorem it is but it follows directly from that the tangent to the cycloid must be perpendicular to the point about which the circle is instantaneously turning - therefore you get a right angled triangle in the circle with one point at the bottom and the other at the top. This can be used via Visual Calculus to get the area of the cycloid easily. Dmcq 10:31, 24 June 2007 (UTC)
Are there any excamples of cycloids in nature or engineering?
When a charged particle is subject under orthogonal electric and magnetic field, its trajectory becomes a cycloid. HotBallah ( talk) 18:49, 14 February 2023 (UTC)
Quoting Article: The cycloid through the origin, generated by a circle of radius r, consists of the points (x, y) with
x = r(t - \sin t)\,
y = r(1 - \cos t)\,
where t is a real parameter, corresponding to the angle through which the rolling circle has rotated, measured in radians (not degrees). For given t, the circle's centre lies at x = rt, y = r.
--- It would seem that you could use degrees, as long as you made 0 < t < 360. The statement that t is measured in degrees is dubious, unless there is a statement saying 0 < t < 2*pi.
Am I missing something? jheiv ( talk) 16:37, 5 May 2009 (UTC)
--Im sorry if im not writing this right, its new to me writing in wiki. the equation that written there for x by not using t isn't right, the right form of the equation is: -sqrt((2 y)/a-y^2/a^2)+cos^(-1)(1-y/a) while a=r. fix it please, I almost got wrong in work for my proffesor. — Preceding unsigned comment added by 85.250.64.229 ( talk) 16:06, 7 June 2012 (UTC)
An editor put in an edit comment saying it was differentiable everywhere, see any textbook. Could they find a citation first please for things like that which manifestly contradict what one can see. Dmcq ( talk)
Oh, sorry, I didn't see this comment. Cycloids are only ever mentioned in math books in relation to parametrized curves. They are in a sense a "classic" parametrized curve. Textbooks never even mention the Cartesian equation because it's unnecessarily complicated. "Regular" curves and "singular points" are elementary properties of differential geometry. See, e.g., Manfredo do Carmo, "Differential Geometry of Curves and Surfaces." (Cycloids are mentioned on page 7, where it says they have singular points at 2pi.)
As for derivations, I did only include the important points. No normal reader of wikipedia is going to know the trig identity that gets you to sin (t/2)--most probably won't even know the substitution rule. And clearly most are not advanced enough to know differential geometry! —Preceding unsigned comment added by 71.185.2.144 ( talk) 01:11, 22 January 2010 (UTC)
But why am I discussing this with you? Go ahead and leave this page as it was, with the claim that cycloids are not differentiable at 2n*pi. I'm moving the discussion to vandalpedia.org, where they appreciate the absurdity of wikipedia. —Preceding unsigned comment added by 71.185.2.144 ( talk) 11:02, 22 January 2010 (UTC)
hey I've seen the cycloid pendulum somewhere and i would like to give an illustration. http://commons.wikimedia.org/wiki/File:Cycloid_pendulum.png But I don't know how to use svg editors.
I hope someone can help to create an svg image or make a thumbnail of my image and then add it to the related part. —Preceding unsigned comment added by Kimkim0513 ( talk • contribs) 12:19, 20 February 2010 (UTC)
The cycloid has been called "The Helen of Geometers" as it caused frequent quarrels among 17th-century mathematicians.
This is a teaser and the reference to a text book doesn't enlighten. What quarrels? Who called it Helen? And who, for that matter, is Helen (for those who don't know their Greek mythology)? — Preceding unsigned comment added by 92.25.9.36 ( talk) 07:31, 30 April 2013 (UTC)
Hello fellow Wikipedians,
I have just modified one external link on Cycloid. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
When you have finished reviewing my changes, you may follow the instructions on the template below to fix any issues with the URLs.
This message was posted before February 2018.
After February 2018, "External links modified" talk page sections are no longer generated or monitored by InternetArchiveBot. No special action is required regarding these talk page notices, other than
regular verification using the archive tool instructions below. Editors
have permission to delete these "External links modified" talk page sections if they want to de-clutter talk pages, but see the
RfC before doing mass systematic removals. This message is updated dynamically through the template {{
source check}}
(last update: 18 January 2022).
Cheers.— InternetArchiveBot ( Report bug) 00:19, 16 August 2017 (UTC)
It seems like we could profitably cut several sentences about speculative attributions that were later shown to be wrong. This might be in scope for some deep dive or historiography study, but doesn't really seem that helpful to readers of this encyclopedia article. – jacobolus (t) 07:32, 1 April 2023 (UTC)