# How to generate the envelope of these ellipses ?

apocase shared this question 3 years ago

How to generate the envelope of these ellipses ?

1

hello

you can test the envelope[] command and report about results

see the help

saludos

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I have searched for envelope, but it can't work. I have seen the example about envelope, there's somehing wrong with it.

1

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When I open the website http://tube.geogebra.org/st..., I see the material with a blue curve(see fig above).

1. x^8+3*x^6*y^2-12*x^6+3*x^4*y^4+84*x^4*y^2+48*x^4+x^2*y^6-12*x^2*y^4+48*x^2*y^2-64*x^2=0

1

hello

I can not see the implicit curve also

you have uploaded a preview (geogebra icon is over the image)

this means that the envelope command was OK when the applet was made but now it does not work

this is an actual bug

saludos

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Thanks, we'll check:

https://jira.geogebra.org/b...

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You need to have only Euclidean steps in your construction like lines, circles and their intersections (or equivalent steps). Maybe it's possible to make your construction in such a way, but it must be difficult. And the more steps there are, the less chance you have that the equation system can be solved before timeout.

Material 67909 works here (5.0.231) on my desktop, but I have a fast computer. Which version do you use? Is your computer quick enough?

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My computer is very slow. I have used it more than five years.

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We managed to find a way to speed up some parts of the computation. 5.0.233 should be significantly faster than the earlier version (it's not released yet).

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i can not see o; GG says o is undefined; then I delete o and type in input line the Envelope[r, A] again.

then GG says undefined inmediatly

saludos

GG5.0231 Windows 7

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Also you can use CopyFreeObject[Envelope[... before you upload it to geogebra.org/materials

1. -64 + 48y² - 12y⁴ + y⁶ + 48x² + 84y² x² + 3y⁴ x² - 12x⁴ + 3y² x⁴ + x⁶ = 0

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Envelope[ ] is working much faster in the new release (5.0.233.0)

http://www.geogebra.org/m/67909

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