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