Is this possible?

Questions
1

Hi all,
I’m looking to add a Desmos activity to a lab that I do with students, but I’m not sure if what I’d like to do is possible.

Question 1: (this is the part I’m not sure if it’s possible) On slide 4, I have the students do a linear regression on the data that they have entered (on slide 2). This seems to be working perfectly - the data transfers from slide 2 and the regression line appears. My question is whether I can use the numbers (specifically slope and y-intercept) from the regression line on slide 5. I want the students to identify the slope and intercept and compare to the equation produced on slide 4. (In later slides, I want do something similar but with the exponential and logistic regressions - I figure that if I know if/how it works here, I can adapt to those later slides).

Question 2: On slide 16, I’d like the second column of the table to automatically calculate the values. A will be a constant that I’ll be able to program in (39 for this year) but I will come from the data entered on slide 2.

Question 3: On slide 21, I want to compare what the students enter in the fourth column to a calculation that is (2nd col - 3rd col)/3rd col. Right now, I have an incorrect computation in there that would actually calculate the number and fill in the table. This would be my 2nd option, but I’d rather have the students calculate it and have Desmos check their answer.

Note: several of the slides are unfinished, as I wanted to make sure I could get the computations working like I’d like before finishing the other pieces.

Thank you for everyone for your help and advice.

https://teacher.desmos.com/activitybuilder/custom/671a48f7ac829761857c6545

2

Slide 4.
If the students do also click “Export model to expression list” than you can read “m” and “b” as numbers of your Graph2.

prova
prova1107×651 51.6 KB

But of course the students also can read that.

3

Thanks! I’ll have the kids do that and adjust my ideas for the questions on the next page.

4

Still hoping for ideas on Questions #2 and #3 if anyone has them.

In the meantime, I’ve run into what I think is a formatting error. On slide 12, I’m having the students do the logistic regression and the suggestion to export the equation. Using the constants I want to display the equation in the note at the top of slide 13.

Here’s what I have as my computation layer:

image
image933×484 38.1 KB

But the equation displays as

image
image679×204 7.38 KB

From what I can tell, “frac” is taking the first two digits of n1 and displaying those as the fraction followed by the rest of the digits and the expression for the denominator.

Can I get this displaying correctly?

Thanks!

5

Add braces to the two parts of \frac:

“Your regression equation is I(t) = \\frac{${n1}}{${d1}}.”

6

This is the best I can think of for Slide 16:


A = 39
f = simpleFunction("I*(A-I)", "I", "A")

c1 = 0.5
c2 = 1.5
# ...

cellContent(1,1): "${c1}" 
cellContent(1,2): "${f.evaluateAt( c1, A)}"

cellContent(2,1): "${c2}"
cellContent(2,2): "${f.evaluateAt( c2, A)}"
#...

Or you could use a graph to create the values for the two columns …

7

This should do:


f = simpleFunction("(a-b)/b", "a", "b")

cellContent(1,4): 
  when isDefined(this.cellNumericValue(1,2)) and isDefined(this.cellNumericValue(1,3)) 
    "${f.evaluateAt( this.cellNumericValue(1,2), this.cellNumericValue(1,3) )}"
  otherwise ""