Teacher summary shows slides as incorrect

Questions
1

I have an odd issue here. The activity is showing the first problem (slide 2) as correct but no others. When in “editing” mode, all slides show as correct. Thanks!

Activity

2

It looks like in your correct sink you have x1 = x1 instead of x1 = x2. But that would make it be correct when students have the right y value regardless of the x value.

I’m not sure what you mean by “showing as correct” though. What are you expecting and what are you seeing?

3

Thanks for replying Daniel and catching the x1=x1.

What I’m seeing on the teacher summary page is that students got slide 2 correct but slides 3-8 incorrect (with correct answers). When I edit the activity and use the “preview” function, they all function correctly and show the check mark.

I have attached images to help clarify. Thanks again.

desmos_1
desmos_11098×226 13.6 KB

desmos_2
desmos_21635×563 46.3 KB

desmos_3
desmos_31626×619 46.1 KB

4

I’ll look again later. One guess I have is that you may need to use the hasResponse sink in the graph, setting it to true when the input button has been clicked.

5

Ok, as far as I can tell, it’s a problem connected to using the regression function like that. I’m not sure why it’s doing it though or how to fix it. Maybe someone else can weigh in on this?

My suggestion is to just calculate the point of intersection algebraically. I redid slide 3 (problem 2) as an example - does that work for your purposes? [Copy of] Solving Systems using the Substitution Method • Activity Builder by Desmos Classroom

6

Can’t speak to why that inconsistency is happening - interesting though and i’d be curious as to why.

But I’d forgo all of the regression and infact all of the solving, and instead do the following:

  • Generate your solution point first, then create equations around that point. Makes for highly re-usable code, easily defined solution bounds, and “nice” answers every time.

  • Don’t validate by solving either, just check that the point you generate in advance as the solution satisfies both equations. This has the advantage of working equally well for nonlinear equations

This approach means you can create randomly generated questions that simply work every time in a wide variety of problems. Hope it helps!