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Topic: [ap-calculus] Need help plaease on 2008 BC MC # 17
Replies: 1   Last Post: Sep 21, 2012 7:47 AM

 Alan Lipp Posts: 1,091 Registered: 12/6/04
RE: [ap-calculus] Need help plaease on 2008 BC MC # 17
Posted: Sep 21, 2012 7:47 AM

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Qayumi,

The notation h(x^2 - 3) like f(x) indicates a function, not a product, and
therefore it is the Chain rule that is needed not the product rule.

Alan

Alan Lipp
Williston Northampton School

-----Original Message-----
From: Qayumi, Enayat [mailto:eqayumi@tusd.net]
Sent: Thursday, September 20, 2012 1:18 PM
To: AP Calculus
Subject: [ap-calculus] Need help plaease on 2008 BC MC # 17

NOTE:
for the new AP Calculus Teacher Community Forum at
https://apcommunity.collegeboard.org/getting-started
and post messages there.
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If h is a differentiable function and f(x) = h (x^2 - 3)

Why is the f'(x) = 2x h'(x^2-3) which will give the correct answer once you
plug in x = 2

And Not

f'(x) = h' (x^2 - 3) + h (2x) due to the product rule? Once you find f'(2)
= h' + 4h, it is not one of the MC options.

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