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Topic: How we get a Ellipse from a Conic, and how we get a Oval from
Cylinder Sections-- knifes that are V and asymmetrical V shaped

Replies: 27   Last Post: Oct 8, 2017 12:41 AM

 Messages: [ Previous | Next ]
 Dan Christensen Posts: 8,219 Registered: 7/9/08
Re: How we get a Ellipse from a Conic, and how we get a Oval from
Cylinder Sections-- knifes that are V and asymmetrical V shaped

Posted: Oct 5, 2017 6:21 PM

On Thursday, October 5, 2017 at 5:55:17 PM UTC-4, qbwr...@gmail.com wrote:
> On Thursday, October 5, 2017 at 1:11:12 PM UTC-7, Dan Christensen wrote:
> > On Thursday, October 5, 2017 at 12:38:55 PM UTC-4, Archimedes Plutonium wrote:
> > > Alright, if our knife in Conic and Cylinder...
> >
> > Archie, for \$52.49, you can save yourself all this embarrassment. Order the "Conic Sections Model" made of transparent plastic. See for yourself -- no knives or scissors required -- that at an ellipse is indeed a conic section.
> >
> > http://www.eaieducation.com/Product/520610/Conic_Sections_Model.aspx
> >
> > If you can't afford it, maybe we can take up a collection for you.
> >
> >
> > Dan

>
> I have seriously considered buying and mailing a model to Archie.
>
> It seems essential that the model be very precisely made.
> It seems essential that the eccentricity of the model be almost 1.
> It seems essential that the intersection be able to be removed, flipped
> in all four possible orientations and replaced to see it is an exact fit.
>
> If any of those were not the case then I'm certain that Archie
> would dream up some tortured convolution to claim that this doesn't
> disprove his delusion and in fact it actually proves he is correct.
>
> It would be cute if there were two spheres of just the right size were included.
>
> I have not found a model online available for purchase that I thought
> would be sufficiently overwhelmingly convincing. I have looked at
> making such a model by hand and I don't think it would be precise enough.
>
> Way back soon after he started screeching his oval nonsense I told him
> that he should go to a machine shop and have them produce a really
> precise model out of steel that would definitely settle this question.
>

Solid steel? That would be a great paperweight. Every geometry and algebra teacher would want one if it was well made. I would buy one if it was under \$100. It would make a nice gift. Have it custom-engraved on the base.

Dan