Talk:Cylinder

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Cylindric section equation source?

The equation for the semi-major axis a in the section Properties/Cylindric sections appears to be wrong. With the current definition, it would imply that the semi-major axis becomes infinite if the cylinder is aligned with the normal of the secant plane. If the equation is changed to a=r / cos(alpha), then the semi-major axis becomes the radius of the cylinder when the cylinder is normal to the plane. What is the source of this equation and is the equation for eccentricity also incorrect?Grumbins (talk) 04:53, 30 June 2022 (UTC)[reply]

definition?

Definition, does the parallell lines need to to be line segments of equal length?

Which parallel lines? Are you referring to §Cylindric sections? In that case, the line segments would be be the height

h

of the cylinder. Andy Dingley (talk) 10:27, 8 March 2017 (UTC)[reply]

Typo? cylinder with arbitrary axis

i think this line: $B=-x\cos(\theta )\sin(\phi )+y\sin(\theta )\cos(\phi )+z\cos(\phi )$

should actually be: $B=-x\cos(\theta )\sin(\phi )+y\sin(\theta )\sin(\phi )+z\cos(\phi )$

Avi --185.46.212.75 (talk) 11:16, 15 June 2016 (UTC)[reply]

Requested Move discussion in progress.

There is a discussion going on at the Talk Page for "Cylinder" to move that page to Cylinder (disambiguation). It is implicit in the proposal that this page would move to Cylinder, but that is not formally part of the proposal. You may want to participate in that discussion. --MrStoofer (talk) 11:10, 9 December 2016 (UTC)[reply]

As the move has been done, the (closed) discussion is now at Talk:Cylinder (disambiguation). D.Lazard (talk) 10:04, 8 November 2017 (UTC)[reply]

Move discussion in progress

There is a move discussion in progress on Talk:Cylinder which affects this page. Please participate on that page and not in this talk page section. Thank you. —RMCD bot 21:46, 9 December 2016 (UTC)[reply]

As the move has been done, the (closed) discussion is now at Talk:Cylinder (disambiguation). D.Lazard (talk) 10:05, 8 November 2017 (UTC)[reply]

"Rod (geometry)" listed at Redirects for discussion

A discussion is taking place to address the redirect Rod (geometry). The discussion will occur at Wikipedia:Redirects for discussion/Log/2021 March 8#Rod (geometry) until a consensus is reached, and readers of this page are welcome to contribute to the discussion. CiaPan (talk) 20:36, 8 March 2021 (UTC)[reply]

"Rod (shaft)" listed at Redirects for discussion

A discussion is taking place to address the redirect Rod (shaft). The discussion will occur at Wikipedia:Redirects for discussion/Log/2021 March 9#Rod (shaft) until a consensus is reached, and readers of this page are welcome to contribute to the discussion. Adumbrativus (talk) 06:09, 9 March 2021 (UTC)[reply]

The page Cylinder is incorrect.

According to James Tanton a cylinder is a made from creating a base shape on a plane, making a congruent shape on a parallel plane and connecting each edge/point to the corresponding edge/point on the other base. This is not the definition that is on the Cylinder page.

The source for this is: [1]https://www.youtube.com/watch?v=XS4xSytnAm8

James Tanton also mentions this in his Geometry course, sold at: https://www.thegreatcourses.com/courses/geometry-an-interactive-journey-to-mastery. Pigly3 (talk) 01:44, 6 December 2023 (UTC)[reply]

There are several related concepts of 'cylinder' used in mathematics, and which one is more convenient depends on context. –jacobolus (t) 03:38, 6 December 2023 (UTC)[reply]

Tanton's definition is equivalent to that of the article's first paragraph. —Tamfang (talk) 07:14, 14 December 2023 (UTC)[reply]

Incorrect height designation in the figure

In the figure "A solid elliptic cylinder with the semi-axes..." height h indicates the length of the side of the cylinder, which is greater than the real height by 1/cos(φ) times, where φ is the angle of the cilinder axis to the normal to the base AAPoul (talk) 02:36, 5 May 2024 (UTC)[reply]

In this particular case, it's clear that the side of the cylinder is perpendicular to the base. This could perhaps be pictured/stated more clearly. –jacobolus (t) 06:08, 5 May 2024 (UTC)[reply]

The caption in the article says that it is an elliptic cylinder that is represented, but most readers will see a circular cylinder with oblique plane sections (that are therefore elliptic). So, the image is not well suited for illustrating the text, and is more confusing than useful. In commons, the only image that I have found that represents an elliptic cylinder is the one that is displayed here, but its labels do not correspond to this article. So, I'll edit the caption, but I am not very happy with this solution. D.Lazard (talk) 08:43, 5 May 2024 (UTC)[reply]

Is the beginning grammatically correct

I'm not an expert, but "has traditionally been" sounds wrong and is might be better. ~2026-24571-03 (talk) 01:02, 22 April 2026 (UTC)[reply]

There is nothing wrong with its grammar. And your disruptive edits to remove it have added a contradiction between the starts of the first and second paragraphs, a worse thing. —David Eppstein (talk) 01:48, 22 April 2026 (UTC)[reply]

The lead is probably not the priority of things to change in this article, but we could plausibly lead with, "In solid geometry, a cylinder is a ...", and then throw in "In higher mathematics, ..." or whatever in a later paragraph, mentioning that the meaning of "cylinder" depends on context. While the lead mentions it, the body of this article doesn't really fully address the topic of the two-infinite-ended (right, circular) cylinder, what is usually meant by the name "cylinder" in many contexts. I'm not sure if there's a more precise name, but it would be great if this article went into more detail about it. I'd expect to find mention that a cylinder is topologically equivalent to a punctured plane, that the logarithm can be considered to map the complex plane to a cylinder and more generally that complex trigonometric functions can be considered to have a cylinder as their domain, that cylinders are intrinsically flat everywhere (developable), and so on. –jacobolus (t) 02:59, 22 April 2026 (UTC)[reply]