Sunday, 13 December 2015

One circle with radius a and another with radius b combine to give an ellipse with width & height (major & minor...


One circle with radius a and another with radius b combine to give an ellipse with width & height (major & minor axes) of a + b and a.

Animation via matthen
http://blog.matthen.com/

#math   #animation   #ellipse
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8 comments:

  1. Viorel Racoviteanu13 December 2015 at 23:44

    Nice. Now I see where you're going. I hope it worked out for you.

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  2. David Chako14 December 2015 at 07:34

    Now start with three circles of whatever radii in a triangle pattern and form all possible ellipses.

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  3. John Bump14 December 2015 at 08:47

    David Chako -- your middle name wouldn't happen to be Lissajous, would it?

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  4. David Chako14 December 2015 at 09:09

    John Bump​ Nah, I am just fascinated by triangles. For example, as you can easily see, any three circles can be abutted each to the other two; their centers then form a triangle. The edge lengths are the sum of the adjacent circle radii. And the second power of the area of the triangle is the product of (the sum of the circle radii) times (the product of the radii).

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  5. anar kissed14 December 2015 at 10:04

    Whenever I see this stuff, my brain insists it should understand but my childhood math fear stomps it's foot and drags me away first. I was told over and over, in stories, TV, and comic books and other kids, that "math is too hard."  So when I faced it, I was loaded with math fear and fear, of course, makes you stupid.  (that's why many citizens are being peddled fear, to keep them stupid, and shopping)
    I got a leg-up on math finally, by dint of great effort, at the end of grade school, but the next teacher of math was incompetent to such an extreme that he became more bullied in school than me or the disabled kids (they were always bullied back then.) That teacher effectively destroyed my math progress and I never recovered, even having to switch from Biology to Linguistics in University simply to avoid failing out.
    I know in my heart I was meant to love math, but never found a teacher to get me there.

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  6. anar kissed14 December 2015 at 10:11

    I think I can remember this as a trick to draw an ellipse with a compass, though.  Only how to do that on a computer I don't know yet, LOL

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  7. Bill Trowbridge15 December 2015 at 02:58

    ann kiszt Try Khan Academy for math from the beginning (or starting anywhere) through calculus and maybe beyond.  It also covers many other topics.  For free. For everyone. Forever.  www.khanacademy.org

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  8. anar kissed15 December 2015 at 09:26

    good tip, thanks!

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