2024 AP Precalculus Free Response #2

Walkthrough of the 2024 AP Precalculus FRQ #2
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[@AllenTsaoSTEMCoach]

Corrections:
Part A) The equation should be a + b ln(92) = 76, so when you solve for b, you get 7.961.

[@moniquemaynard2073]

C. A_t < G(t) because the secant line of A_t will always be below the concave down curve for G(t) on the interval.

[@stephenbeck7222]

For B (iii) the intention on this part (for almost all different ways that Biii could be asked no matter the form) is to discuss the concavity of the model. For a concave down curve like the log function here: If the average rate of change is formed over the interval (m,n), then the secant line will always be below the model for points inside (m,n) and above the model for points outside (m,n). And of course the opposite over/underestimates for concave up models. I think FRQ2 will always be using a quadratic, exponential, or logarithmic model (or something very similar) where you can tell the concavity just from the sign/magnitude of the parameters you found in part A, without even needing to graph.

[@AllenTsaoSTEMCoach]

Yeah I see that now. Interesting how they ask and have students look at it that way.

[@zacharygibson8344]

If kept in thousands, would it only be one point off b/c of error carried forward?

[@Wish987]

Why would keeping in thousands lose full credit it says nothing about specific units

[@wolfcanyon]

7:28 POV you’re trying not to say the natural logarithm function is concave down on a precalc frq 😂

[@AllenTsaoSTEMCoach]

Haha I know. I forgot if they talk about concavity in the precalculus course description. I should have just looked it up

[@hanchengpeng2266]

Bro i kept it in thousands💀 Will i get partial credit?

[@erinzhang303]

That’s what I did 😭

[@nadobot7626]

Do u still get credit if you don’t put the unit after the answer?

[@BaDaBaBaBa_wiwi]

I was gonna ask, you are not alone

[@stephenbeck7222]

For B (i), you shouldn’t need to put units. The units are already in the question and they’re pretty good about asking for units specifically when they want them.

[@aaritatreja9766]

Shouldn't it be a + b ln(92) = 76 for the second equation, because the equation is a + b ln (x + 1)? Doing so gives me 7.961 for (A, ii)

[@Blosp]

it should be a + b ln(91+1) = 76 and a + b ln(0+1) = 40 cause i don't think you should simplify the equation

[@riven7718]

Yea u are right it should be 92

[@solquiroz8437]

what if i kept my answers in thousands?

[@jordan8010]

I kept in the thousands😢

[@hanchengpeng2266]

Same, do you think we’ll get partial credit?

[@jordan8010]

@@hanchengpeng2266 hopefully