Talk:Ellipse

Something is wrong with this formula:

And the general equation of an ellipse in polar coordinates is
<math>r = \frac{1\left( 1 - e^2 \right)} {1 - e \cos \theta}<math>

What does "general equation" mean here?

The images look a bit fishy to me. Aren't the two foci too far apart? Also, one of them seems to be closer to the ellipse than the other one. AxelBoldt 07:48 Feb 9, 2003 (UTC)

The first 1 in the formula should be an a (so it's not a general equation at all - it's essentially the same as the polar coordinate equation that's already in the article).

I also thought the foci in the images were too far apart, but when I measured them they seemed about right (well, the one on the left anyway). But I may do some neater replacements somewhen. --Zundark 16:34 Feb 9, 2003 (UTC)


Q: What tools are used for drawing the figures? Are the source files of the images avairable? I'm writing ja: page of ellipse (ja:楕円). --HarpyHumming 11:53, 27 Feb 2004 (UTC)

I don't know anything about the third image. The first two images were originally done by someone else, but they were somewhat messy, so I redid them, copying things like the arrows and the text from the originals. I used some experimental software of my own design to draw the ellipses themselves, and did the rest of the work in the GIMP. The PNG files were processed by pngrewrite and pngcrush (or maybe pngout) to reduce the filesize without affecting the image. So there are no source files, just the PNGs. --Zundark 13:47, 27 Feb 2004 (UTC)

Formula for case where minor/major axis are not parallel with x/y axis is missing. Tomislav

Yeah, someone needs to include that. I might be able to later, but I'm not sure. pie4all88 01:27, 20 Aug 2004 (UTC)
All right, I have it put in. Hopefully it helps. pie4all88 01:36, 20 Aug 2004 (UTC)

There's an electronic group called Oval. I wanted to write an article about them, but Oval redirects here. What I'd like to do is add a line to the top that says "Oval is an electronic group" and have the word Oval link to a page "Oval (band)". I really dislike automatic redirects... IF I don't get any negative feedback on this in a few weeks, I'll go ahead and do it.

Hwarwick 8:32, 07/06/04

The electronic group was already mentioned at the bottom. I've moved the disambiguation to Oval, which shouldn't have redirected here anyway. --Zundark 07:27, 7 Jul 2004 (UTC)

Excellent! Thanks much!

Hwarwick 10.04 7 JUL 04

How far off-topic is Newton?

Do we really want to tell the history of Kepler's laws of planetary motion including Newton's deduction of them from his law of universal gravitation here on the ellipse page? Or would that history be better told on one of those two other pages? Ben Kovitz 16:25, 4 Dec 2004 (UTC)

Yes, it's a bit off topic and it is closely explainded on other pages. But it's only one sentence and it provides the basic idea about the problem of planetary orbits which is closely related to the ellipse topic. I think it doesn't harm this topic and sometimes may lead the reader to further readings. That's my humble opinion.
-- Egg 19:13, 2004 Dec 4 (UTC)
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