Objects dependent on sliders not working

Ben Smith shared this problem 2 months ago

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Hi, I'm trying to make a demonstration for understanding second-order partial derivatives like in this youtube video: https://youtu.be/6U2rTOhS3fA following his instructions here: https://drive.google.com/fi...

It seems pretty simple, but it is not working for me; geogebra is being very weird about the variable name yc, for some reason. Sometimes, when I typed the curve(...) function, with yc in it, it would replace the yc with zero, so that it wasn't dependent on the yc slider at all. Clicking on the curve to open the definition and properties showed that it was still in terms of yc, but the graph showed it stuck at y=0 no matter what the yc slider did. I tried it again with different variable names and it happened again. Sometimes, the first curve was fine but the second curve had the problem. Sometimes the first curve had the problem. It happened on both geogebra.org and on the geogebra 5 desktop app. There's something I'm missing about dependent objects based on sliders.

It is doing other weird stuff. Like when I try to delete everything and start over, it still has variables bound to the deleted things. For example, I made a slider named yc, then I renamed it to k, then I deleted everything. Then I try to make another slider called yc, but in the algebra view, what shows up is "a = k". What the heck is going on?

The same problem

Comments (4)

Simona Riva ● 2 months ago

I see this yc thing.

Here it's the file I've created following the instructions in your Google doc. (I haven't created it all, just till f'_x.

The weird thing is that it doesn't work when you create it, but if you save, close and reopen the file it works.

(I've noticed this because my file had yc stuck at 0 in the curve definition when I've created it, then I reopened the file to test another thing and it worked)

I'm looping this to the developers.

Files: Part_Deriv.ggb

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Ben Smith ● 2 months ago

Thanks. Saving, closing, and reopening fixed it. But then I had to do that again every time I created a new object dependent on yc.

By the way, the youtuber, turksvids, is using a mac. I asked this question on reddit, and a mac user there also had no problem. I am using windows 10 (up to date, on a MS surface pro 6).

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Michael Borcherds ● 2 months ago

Thanks, - as a workaround you can copy & paste this rather than typing it:

Curve(t, yc, f(t, yc), t, -100, 100)

(or save/reload is also OK as Simona says :) )

BTW you have a typo in your PDF "play" -> "plane"

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Ben Smith ● 2 months ago

Thanks! I tried copying and pasting before, and that didn't work. But closing and opening the file does work. I can't take credit or blame for the PDF instructions, by the way; they were written by the dude who made the video, turksvids.

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