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Unformatted text preview: t (b) because the meaning
given does not address the time interval over which the average was computed. In part (c) the student earned both
points. The first point was earned for correctly providing the definite integral that represents the number of
hundreds of entries processed between 8 P.M. and midnight. The second point was earned for subtracting that
value from the initial condition of 23 hundred entries in the box at 8 P.M. to obtain the answer. In part (d) the
student earned the first point for setting P′( t ) = 0. The student does not consider the endpoints as candidates, so
no additional points were earned. © 2010 The College Board.
Visit the College Board on the Web: www.collegeboard.com. AP® CALCULUS BC
2010 SCORING COMMENTARY
Question 2 (continued)
Sample: 2C
Score: 3 The student earned 3 points: 1 point in part (a), no points in part (b), 2 points in part (c), and no points in part (d).
In part (a) the student sets up a correct difference quotient based on the values in the table and correctly evaluates for
the numerical answer. In part (b) the student subtracts the function values at endpoints of the subintervals rather
than adding them. The student interprets the integral expression as an average rate rather than an average number.
In part (c) the student’s work is correct. “700” was accepted because of the units in this question. In part (d) the
student never considers P′( t ) , so no points were earned. © 2010 The College Board.
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This note was uploaded on 08/22/2013 for the course CALCULUS AP taught by Professor Staff during the Fall '11 term at Lakota West High School.
 Fall '11
 staff
 Calculus

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