For my activity, I used a screencast to demonstrate how to use a feature of Desmos that will be helpful for their activity. I showed how students can use a slider to see the effect that a constant value has on a given graph of f(x). I demonstrated the effect that c, a constant, has on a graph of f(x) = c x2. I showed how once a constant is used in an f(x) function in Desmos, there is an option to add a slider for c.
Once the students have watched the demo, I would ask them to do the same for the functions, f(x) = a + b x + c x2. I would ask them to describe the effect of a, b, and c as they become greater, smaller, and negative. I would also ask them to look at f(x) = sin(a x) vs f(x) = b sinx and compare the effect of a vs. b.
This screencast helps students understand how to use this feature in Desmos if they do not yet know how to use it. The activity goal is for student be able to understand visually the effect that constant have on the f(x) functions they have been looking at.