# Geogebra

Posted on August 2, 2019

It’s the penultimate Friday Off and I did my ’30 miles by noon’ by 11 on the Trek… and it’s time to play with doing things in Geogebra that are over my head š

There is an interactive number grid there that I started to play with for making interactive visuals for “counting off” the times tables, except that it’s taken a back seat to my mad quest for spaced retrieval.

It does, however, do a cool thing with Sequences where instead of just writing in all the numbers, it’s generated with a line of code that not only generates all the numbers but puts them in the squares on the grid! To wit:

Sequence(Text(If(a, i, i – 1), Centroid(Element(list3, i)) – (0.3, 0.2)), i, 1, 120)

So… I don’t want to put *all* the facts out there, but I do want to make a list of them.
The ‘if’ part is because it includes the option of starting with 0 or 1; a is “first number is 1.”

So, I need to figure out the syntax for including ” x ” in between the numbers… no luck in the “check as you go” tutorials (which don’t seem to work in Chrome?)… and… the videoss are focused on the buttons and properties and all that. SO I have to figure out this example š

Okay, that’s not working. Since I don’t really want a sequence *of* texts… I just want a list of them to pull from… I should probably make my two lists and then do a sequence of texts… because that sequence is pulling from the already made lists of points. … except if I just make the list, it doesn’t make a variable. (I shouldn’t need to do that.)

ELEMENT. ELEMENT.

So. Text (I HATE THAT IF YOU LEAVE THE WINDOW YOU LOSE THE COMMANDS. Note to self: at work grab a laptop so this doesn’t happen… ) If I click on settings, then for some reason … the algebra takes up the entire monitor and I can’t see the settings. No, I have to go click on the upper right corner and count to five, at which point things will come back but of course with the ‘settings’ blocked by doing that so I have to click on “settings.”

Text(Element(l1,1) works … now I need to make a sequence that lets that 1 start at 1 and go to 4.

Hmmm. Lots of fails. Feels like I’m asking for variables that don’t exist. So I’ll try just making a list not of points, but of numbers. Now, we have done this before and it didn’t work. So … when it doesn’t… it’s laundry time š

It doesn’t work because … there *should* be a way to have the variable in the sequence – there *seems* to be!!! — but when I do it, it doesn’t happen, set break time

… and it didn’t. I copied the first sequence from the one that worked. So. I might just have to write them all in. (I would have had them all written in had I started that when I started trying to figure this out.) Break time: N + 22 (2:00).

Maybe I just need to make a list???

(It’s hard to tell when somebody has put in this = and it *turns into* something else … anyway I’ve tweeted it to GGBCHAT and … hope it is easier to answer than my previous tweets about specifics …

Text(Element(l1,1) works … now I need to make a sequence that lets that 1 start at 1 and go to 4. THIS is where I feel like I should be able to make that one a variable… and then let the variable increment.

Almost break time. NExt strategy: to copy the first four things from the other one and then change things and see what happens. Now, typical Geogbra experience — I’m following same order of construction but when I literally copy exactly the same thing into mine it doesn’t work. Why? Because in *his,* the default name is list1, and in mine, it makes it l1, so … bad values.

Here it is so I can copy it:
Sequence(Sequence(Polygon(Element(list1, i, j), Element(list1, i, j) + (1, 0), 4), j, 1, 10), i, 2, 13) No, I didn’t not snip it all. I did it right, FYVM.

Note… this could be a good reason *not* to make meaningful names for things but… I don’t know.

(yay! got answer… but it *is* break time because I need to re-think how I’m doing this…)

and yay!!! By the time I was lathered… I knew what to do. 3 minutes into it and Sequence(Sequence(Text(i + ” x ” j), i, 0, 10), j, 0, 10) š š

Now, it’s still a fact that … it would have been faster to type it in, BUT now this exists š I don’t have to do the process again.

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