Talk:Ellipse/Archive 1

Probably this picture could be used: [1] (Fig.207), see [2]. Boris Tsirelson 05:12, 2 May 2010 (UTC)

I added two pictures from that source. Incidentally, feel free to change/adapt/add stuff, CZ is a wiki, you know. --Paul Wormer 12:08, 2 May 2010 (UTC)

trammel, figs.

1. I have doubts about fig.2; it seems to me that the central line should overlap with the red and the green ellipsi, until their centers.
2. I like the deduction of the Trammel. Who was Trammel? What century, what country did he/she live?
3. How about to borrow the animation of the trammel device grom wikipedia; I mean, http://en.wikipedia.org/wiki/File:Bsgrinder.gif ?
4. As for the drawing with a string... I used the loop to draw ellipsi; then the whole ellipse can be drawn at once. (The lenth of the string should be extended with a piece of length equal to the distance betwin the focuses.)
Dmitrii Kouznetsov 18:30, 2 May 2010 (UTC)

Dmitri, I'll try to follow your advice on fig. 2 later today. I made it with Autocad and have no code. If you can make a better picture I would appreciate it. Look in an English dictionary for trammel, it is not a person. (I didn't know the word either). We are not allowed to use animated gifs, or using stuff from Wikipedia. Material from WP is only allowed if the real name of the author is known and we have written permission. With regard to the loop: I followed the description and the picture in the book. Boris suggested that I include the picture and I wrote the text to match it.

I have a question to the mathematicians: two things are missing. The quadric Ax²+Bxy+Cy²+Dx+Ey+F=0 and the definition by means of directrices (vertical lines at fixed distance from foci). Is that bad?--Paul Wormer 06:13, 3 May 2010 (UTC)

Approvals etc

Let me express my opinion, probably quite controversial.

0. It is not the question, "is it bad?"; it is THE question, "should the article be approved?".

1. The approval mechanism is THE feature of CZ. We should not dream of Google juice when our articles are "unapproved, subject to disclaimer, not to be cited".

2. Unfortunately, in order to approve advanced math articles we need many (20..100) active math editors (then it will be reasonably probable to find at least two editors competent in the favorite matter of an author).

3. Fortunately, in order to approve undergraduate math articles it is enough to have just two active math editors, provided that... see (6) below.

4. Two necessary conditions for approval: (a) not misleading; in math context it just means, no errors; and (b) useful.

5. Desirable but NOT NECESSARY, and in fact not reachable: unimprovable. It is always possible to add something, or make a small improvement. "Useful" does not mean "as useful as at all possible". I understand that in a political context, to miss some aspect may be an intolerable bias. But in math context this is not an issue. Some aspect is missing? Well, work on it AFTER approval, if you can and want.

6. Thus, I call math editors to strive to approve articles (satisfying the two necessary conditions), not to find a reason to delay the approval.

A1. Regretfully, today we have at most two active math editors: Peter Schmitt‎ and Dmitrii Kouznetsov. (I would be happy to be wrong in this point.) I've asked both about possible approval of "Ellipse". One did not reply (yet), the other made some remarks.

A2. I can apply for the editor status, if I'll feel that this will help. That is, if at least one existing editor will support my attitude expressed above.

Boris Tsirelson 11:15, 3 May 2010 (UTC)