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## AP®︎ Calculus AB (2017 edition)

### Course: AP®︎ Calculus AB (2017 edition)>Unit 12

Lesson 1: AP Calculus AB 2017 free response

# 2017 AP Calculus AB/BC 4b

Potato problem from 2017 AP exam (Question 4, part b). Taking the second derivative using the chain rule to think about concavity.

## Want to join the conversation?

• is it an underestimate because you assumed the same dH/dt for all t>0?
• Since the problem stated that H is always greater than 27, then dH/dt will always be negative. Since the second derivative is (-1/4)(dH/dt), the second derivative will always be positive. A positive second derivative means the curve is concave up, so the curve will begin to curve up while the tangent line will continue its same downward path. Thus the tangent line will be below the true curve, meaning it will underestimate.
• Does anyone have an example of any AP solved exam? I'm just curious to know how we would flesh out our language.
• I believe on the College Board website you can download the answer key to the 2017 exam. You can see a solved exam there.
• When answering the question, how should I format my answer? Do I have to answer in paragraph form?