2023 AP Calculus AB Free Response #6

Walkthrough of the 2023 AP Calculus AB FRQ #6

[uyentrandinh]

What should my composite score be to get a 4?

[supermemobee]

On part D I ended up taking a roundabout way and since dx/dt is a fraction i said dx = 2 and dt = 3, then found dy/dx was -4/3 and got dy by multiplying that by 2 and dy/dt by dividing -8/3 by 3

[richnort]

I wasn’t sure i got part c right but i’m glad i did🙏

[jacklokensgard]

on part b, would the point 2, 2 be a horizontal tangent because when you plug it into dy/dx, you get 4/0?

[michael]

On the exam I figured out a pretty creative solution to D and I want to know if you think it works.

We already know dx/dt, and we know that dy/dt = (dy/dx) * (dx/dt).

Given the coords and the fact that we already derived dy/dx, I plugged the given coords into the "differential equation" (basically the "dy/dx" equation) we got in (a).

Plugging in for x and y gives us a dy/dx = -4/3

Now just do (-4/3) * (2/3) = -8/9

A simple solution (maybe too simple?) but I was really patting myself on the back for this shortcut. Do you think this would get full credit for whatever points they give for your work/process?

[shreyakarumuri]

could you multiply dx/dt by dy/dx to get dy/dt or no

[seabassnotafish]

on part c, would (1/2, -1) also be another point since y = -1 and 1 for the equation y^3 = 1

[vanessadeborah]

Pretty sure I mixed up b and c but everything else good