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Radius of a circle becomes 0
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There is a difference between version 3.2 an newer versions (3.2.45.10):
Existing a slider (r) for real numbers between 0 and 5;
a line with a point (A) on it;
a circle with midpoint A and Radius r;
intersection point (C) of the line and the circle.
If the radius becomes 0, the intersection point (C)
* does not exist longer in the newer versions, but it
* does exit in version 3.2
So a few constructions working in 3.2 do not work in the new versions.
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May be ...
the value was not yet exactly zero? If it was only rounded to zero the intersection point could still excist ... just an idea :confused:
Birgit
Please post a ggb file
The file "KreisRadiusNull.ggb" works correctly. If I drag the slider (r) to 0, the point C exists furthermore. This is what you will expect.
When I start the file "Würfelschnitt.ggb" and I drag the point E''' to an end of the arc, the pictures are not complete; parts of the elevation and as a result of it parts of the 'Schrägriss' (in german) vanish. This was the point, when I found this problem. I did the construction in version 3.2 at home. When I showed it to my students working under a newer version, the problem occurs.
Now:
Reloading "KreisRadiusNull.ggb" after closing "Würfelschnitt.ggb", the result when I drag the slider to 0 is
I hope, you can reproduce the problem.
Greetings Rudi
https://ggbm.at/546601
https://ggbm.at/546603
It's a problem in your construction I think:
C''=Intersect[f_1, e_1, 2]
When f_1 has zero radius, there is no second intersection point so C'' becomes undefined.
You could try something like:
If[IsDefined[C''], C'', Intersect[f_1, e_1, 1]]
Thank you.
I use instead of the compass now a vectoraddition and it works fine.
Rudi
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