Finding the functions between these points

anas4503 shared this question 9 months ago

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I have the following vase and I wish to find the functions between each of the points so that I can integrate it to find hte volume. So how do I find the functions? I saw one can do fitpoly command but that doesnt look like itll work with these points:

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Comments (18)

ccambre ● 9 months ago

Use more points and experiment with the degree.

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Michael Borcherds ● 9 months ago

Also try Spline() or you can draw a freehand function with the Freehand Shape tool

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Juan Carlos Ponce Campuzano ● 9 months ago

Try this applet that uses trigonometric interpolation.

First draw your shape with Penstroke and then click on Plot Epicycles. Finally click on Equation button.

0e57e93ad6d0acde1a6b0babed418ac8

Files: dft-trigonometr...

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Michael Borcherds ● 9 months ago

Very cool! Is that uploaded to geogebra.org?

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mathmagic ● 9 months ago

por fin la busqueda sirvio para algo

https://www.geogebra.org/m/dubc9swj

pero me gusta mas el del post

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Juan Carlos Ponce Campuzano ● 9 months ago

There is one but it I have not published it because the results are quite different online compare to the offline version.

https://www.geogebra.org/m/tgbjxehq

I also made it with points:

https://www.geogebra.org/m/sgmheqay

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Michael Borcherds ● 9 months ago

Thanks, that's amazing!

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anas4503 ● 9 months ago

Hello Juan,

Thank you for the reply, I tried using this trigonometric interpolation program but I dont know how it works. Is it possible you can show me how to and help me with this? I am in my last year of high school and this assignment weighs 25% of my final grade, so I would really appreciate if you could show me how to work it out.

Kindest Regards,

Anas

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Juan Carlos Ponce Campuzano ● 9 months ago

To work out the trigonometric interpolation you can consult this material:

http://www-users.math.umn.e...

You are going to need some time to study it but I think I may help. Cheers!

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anas4503 ● 9 months ago

Thanks for the theory part, I think I now know what an epicycle is. But when using your program, it makes the epicycles but then it doesnt display the trigonometric equation.. How would I do that?

I have attached my work if you want to see if it is possible.

Files: 3d objekt matia...

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anas4503 ● 9 months ago

For example, I've attached an image that shows me work where I roughly estimated the points of my vase onto that program you showed me. But then when I click on plot epicycles it gives this: (attached), and I cant get the equation out of it.

Files: billede_2020-12...

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Michael Borcherds ● 9 months ago

Epicycles won't give you an equation. Try FitPoly() or Spline()

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Juan Carlos Ponce Campuzano ● 9 months ago

If you want the equation you need the file shared at the beginning:

https://help.geogebra.org/t...

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mathmagic ● 9 months ago

es evidente que si nos compartiera el archivo con la imagen de la botella ya le habríamos dado las funciones necesarias para saber el volumen de la botella, pero como las personas parecen cada vez más reacias a compartir sus *.ggb estamos dando indicaciones una y otra vez, lo que a la larga supone una perdida de tiempo

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mathmagic ● 9 months ago

Juan Carlos

como no me funciona no entiendo el funcionamiento

lo he abierto y el script del boton1 me abruma, pero cuando hago clic en el boton plot epicycles me crea otro stroke que tiene el grafico nulo y no hace nada más

puede que el script no funcione en ver5 escritorio

¿es necesario abrirlo online tal vez?

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