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Topic: [ap-calculus] Need help plaease on 2008 BC MC # 17
Replies: 1   Last Post: Sep 20, 2012 4:48 PM

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Richard Sisley

Posts: 4,189
Registered: 12/6/04
Re: [ap-calculus] Need help plaease on 2008 BC MC # 17
Posted: Sep 20, 2012 4:48 PM
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This ap-calculus EDG will be closing in the next few weeks. Please sign up for the new AP Calculus
Teacher Community Forum at
and post messages there.
On Sep 20, 2012, at 1:18 PM, Qayumi, Enayat wrote:

> ---------------------------------------------------------------------------------------------
> 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)

There is a difference between f(x)=h(x)*(x^2-3) and f(x)=h(x^2-3). In the first case f is given as the product of a function named "h" and a second function (lets call it "g") with g(x) = x^2 - 3. so f(x) = h(x) * g(x). In the second case f is given as the composite of h following g. So f(x) = h(g(x)). Try the Chain Rule instead of the Product Rule.


Richard Sisley
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