Sequences & Exponential Functions (College Board AP® Precalculus): Exam Questions

4 mins4 questions
1
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1 mark

The function f is given by f \left(x\right) = 4 \cdot 49^{x}. Which of the following is an equivalent form for f \left(x\right) ?

  • f \left(x\right) = 2 \cdot 7^{2 x}

  • f \left(x\right) = 4 \cdot 7^{x / 2}

  • f \left(x\right) = 2 \cdot 7^{x / 2}

  • f \left(x\right) = 4 \cdot 7^{2 x}

2
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1 mark

The exponential function f is defined by f \left(x\right) = a b^{x}, where a and b are positive constants. The table gives values of f \left(x\right) at selected values of x.

x

0

1

2

3

4

f \left(x\right)

48

24

12

6

3

Which of the following statements is true?

  • f demonstrates exponential decay because a > 0 and 0 < b < 1.

  • f demonstrates exponential decay because a > 0 and b > 1.

  • f demonstrates exponential growth because a > 0 and 0 < b < 1.

  • f demonstrates exponential growth because a > 0 and b > 1.

3
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1 mark

In a certain experiment, the number of cells in a culture can be modeled using a geometric sequence, where the first day of the experiment is day 1. The number of cells on day 3 was 1,500, and the number of cells on day 9 was 96,000. What was the number of cells on day 6 based on the model?

  • 48{,}750

  • 12{,}000

  • 6{,}000

  • 375