How I use GeoGebra to make animations in videos (Part I)

I said I use GeoGebra to make animations in videos, but how do I do this? Here is part 1 of 2 of the basics.

Please view this webpage on a PC, because the GeoGebra embedding does not work well on mobile.

Sliders

The basic tool to create any animation in GeoGebra is the slider. In the applet below, you can try to slide the white sliders from left to right to see how the red dot moves, and you can also see how I created the points and the segment. If you want to download the GeoGebra file (*.ggb), first download the GeoGebra application here (select the GeoGebra Classic 6), and then click the button below.

In the GeoGebra app, you can export it as a GIF file, but in this case, the result does not look great.

Exporting the above GeoGebra file to GIF, but it isn’t “smooth”.

It does not look smooth at all. I mean, smooth in the mathematical sense, but it is boring to see the movement to be that uniform. Sliders are built in to move uniformly, but you can modify it to make it more interesting. The effect we want would be to start slow, accelerate, then decelerate near the end. To put it more graphically, here is the graph of the “distance travelled” of the red dot versus “time” passed.

A “distance-time” graph for sliders

The yellow line indicates a uniform motion, like the one above. But in order to have a “smoother” motion, the blue curve is more like what we want. There are many ways to implement this, and one of the ways is the following curve:

y = x - sin (2πx) / (2π)

This is exactly what I do normally in my videos. Let’s see how I do this in the GeoGebra file.

The result of this, after I hide the sliders, looks like this:

This looks significantly more interesting than just uniform motion. This is just one of the two parts of the basics. The other is the Parametric plot and Sequence functions in GeoGebra, which we will discuss in another blog post.