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Best answer by ValeryOchkov

The article

http://twt.mpei.ac.ru/ochkov/7-curves.pdf

7 replies

25-Diamond I
July 1, 2016

Why not stay with the four basic operations and replace one of the points by a straight line?!

We have (with a=distance from the focal point and b=distance from the straight line):

a+b=const -> parabola

a-b=const -> parabola

a/b=const -> conic (a/b>1: hyperbola, a/b=1: parabola, a/b <1 ellipse)

a*b=const. -> ???

24-Ruby IV
July 2, 2016

Seven is one fine number - for not.

25-Diamond I
July 2, 2016

Why be content with seven when you can have eleven or more ?

As it looks you like playing around with that kind of curves and also have the time doing so, her some additional ideas.

Stay with simple sum and used weighted distances. Something like two "focal" points 2a+3b=const when a and b are the distances from the "focals".

Or use more than one focal point. What about a curve, where the sum of the distances from three points is constant.

Regards

WE

24-Ruby IV
July 3, 2016

1. black+blue

1-ellipse.png

24-Ruby IV
July 3, 2016
24-Ruby IV
July 3, 2016

3. black * blue = const (ovals Cassin)

3-oval.png

25-Diamond I
July 3, 2016

You demanded

> a • b • c = const

and as it was quite easy to change the sheet with the constant sum to provide a constant product, so here it is.

25-Diamond I
July 3, 2016

And here is the (IMHO less interesting) animation showing the distances:

24-Ruby IV
July 4, 2016

Werner Exinger написал(а):

And here is the (IMHO less interesting) animation showing the distances:

Animation

Video Link : 7022

24-Ruby IV
July 4, 2016

Mathematica has only 4 curves - see please Wolfram Demonstrations Project

Mathcad - seven!

25-Diamond I
July 4, 2016

There are so many other possibilities and ways to define that kind of curves, but there may be a sense and deeper reason why Wolfram is limiting itself to the four basic operations and is not using other functions like exp or ln.

24-Ruby IV
July 5, 2016

Werner Exinger написал(а):

There are so many other possibilities and ways to define that kind of curves, but there may be a sense and deeper reason why Wolfram is limiting itself to the four basic operations and is not using other functions like exp or ln.

But perhaps Wolfram does not have the great imagination as we have

24-Ruby IV
October 27, 2016
24-Ruby IV
November 3, 2016

The journal Cloud of Science with the article in attach.

Seven computational curves or Apollonian bicycle

Valery F. Ochkov, Alvaro Diaz Falconi

(Some words in it about W. Exinger)

ValeryOchkov24-Ruby IVAuthorAnswer
24-Ruby IV
December 16, 2016
7-Bedrock
February 8, 2017

Pouvons nous representer en Mathcad l'ensemble des Julia z --> carre(z) + 0,25 ?

Can we graph in Mathcad the set of Julia z---> z^2 +0.25 ?

Like in : Dimensions / episode 7, min 7:42 ?

Best regards, Liv.

25-Diamond I
February 8, 2017

> Can we graph in Mathcad the set of Julia z---> z^2 +0.25 ?

Sure!

If you search the forum or the net you should find some nice examples how to create pictures of Julia- and Mandelbrot sets.

Here are just examples for 2 different approaches:

http://www.adeptscience.co.uk/products/mathsim/mathcad/fractals-in-mathcad.html   (see at the end for a link to the Julia worksheet)

http://ocw.nctu.edu.tw/upload/classbfs120905452520455.pdf

Maybe worth opening a new question/thread if you already tried and experienced difficulties.