Talk:Astroid

Non-equivalence of equations in the complex plane
Note that the equation :$$x^{2/3} + y^{2/3} = 1$$, when considered in the complex plane, is not equivalent to
 * $$(x^2+y^2-1)^3+27x^2y^2=0.$$, which has other

complex branches. It would be nice to give a reference to Puiseux series (http://en.wikipedia.org/wiki/Puiseux_series) -- M.L. Maxim Leyenson 18:41, 22 April 2007 (UTC)

No more "Popular Culture"
I deleted the Popular Culture section. It had been tagged for 11 months because it had no references.

The Steel logo obviously is not composed of true astroid shapes, but merely four-lobed curves reminiscent of astroids. (The true curve is noticeably more shallow than the pretty shape used for the logo.) I doubt that any of the other shapes cited were any more accurate than the steel logo. The Price is Right article did not even mention astroids or display one in the several images of the show.

Further, I question the need for a "Popular Culture" section for a mathematical curve in the first place. If a mathematical curve has a practical application (such as gear teeth for involutes of circles, or suspension bridges for catenaries) that is a different matter.

Dlw20070716 (talk) 16:00, 15 July 2011 (UTC)

Astroid, or Astroide?
In Spanish, French and Italian the name of this curve is spelled 'astroide', with accents suitable to those languages. Normally a foreign name is spelled the same in English as in the foreign language with omission of any accompanying diacritics. In this case the addition of the final e (which shall remain silent as usual in English) is particularly wanted as it helps to distinguish it from the too similar 'asteroid', which leads much too far afield for appropriate denotation. I have also seen this 'astroide' spelling used in English, most notably in the examples for the Euler mathematical computer program. And again in an advertisement for a trucker baseball cap(!) with this curve in its design. Unfortunately, I do not consider either of these sources particularly trustworthy in matters related to proofreading.

Dlw20070716 (talk) 16:45, 15 July 2011 (UTC)

Actually astroid and asteroid etc are just spelling variations of one Greek word. (Introducing a difference in meanig between them sounds quite artificial to me; I suspect that all of them can be used with both meanings (curve, celestial body), which is maybe less efficient, but maybe more correct, philologically). --pm a 06:34, 18 July 2011 (UTC)