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AP Calculus

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Special Focus: The Fundamental<br />

Theorem of <strong>Calculus</strong><br />

2002 AB4/BC4<br />

Free-response question AB4/BC4 from the 2002 <strong>AP</strong> Exam gives an example of this<br />

application of the antiderivative part of the FTC. Students were not allowed to use a<br />

calculator on this question.<br />

The graph of the function f shown above consists of two line segments. Let g be the<br />

function given by g( x) = ∫ f ( t)<br />

dt . 0<br />

(a) Find g( −1 ),<br />

g ′( − ),<br />

x<br />

1 and g ′′( −1<br />

).<br />

(b) For what values of x in the open interval (–2, 2) is g increasing? Explain<br />

your reasoning.<br />

(c) For what values of x in the open interval (–2, 2) is the graph of g concave<br />

down? Explain your reasoning.<br />

(d) Sketch the graph of g on the closed interval [–2, 2].<br />

We will focus on parts (a) and (b) here. Students needed to use the Fundamental<br />

Theorem to determine that g′ ( x) = f ( x) in order to answer part (a). For part (b),<br />

some students attacked the problem by trying to make an area argument. Others used<br />

the fact that g′ ( x) = f ( x) and that from the given graph f ( x) > 0 on − 1 < x < 1, so f<br />

is increasing on the interval −1 ≤ x ≤ 1. The students who used this last argument were<br />

much more successful than those who tried an area argument.<br />

12<br />

<strong>AP</strong>® <strong>Calculus</strong>: 2006–2007 Workshop Materials

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