Home / AP Calculus BC : 1.9 Connecting Multiple Representations of Limits- Exam Style questions with Answer- MCQ

AP Calculus BC : 1.9 Connecting Multiple Representations of Limits- Exam Style questions with Answer- MCQ

Question

The table below gives selected values for a function \( f \). Also shown is a portion of the graph of \( f \). The graph consists of a line segment for \( x < 3 \) and part of a parabola for \( x > 3 \). What is \( \lim_{x \rightarrow 3} f(x) \)?

\( x \)2.92.952.992.9983.0023.013.053.1
\( f(x) \)1.6501.6251.6051.6011.6021.6121.6591.716

A) 1.6

B) \( \frac{1.601 + 1.602}{2} \)

C) 2

D) The limit does not exist

▶️ Answer/Explanation
Solution
1. Graph Analysis: The graph shows continuity at \( x = 3 \) with values approaching approximately 1.6 from both sides.
2. Table Analysis: As \( x \) approaches 3 from both sides (2.998 → 3.002), \( f(x) \) approaches ≈1.6.

3. Linear Segment Calculation:

  • Slope \( m = \frac{1.625 – 1.650}{2.95 – 2.9} = -0.5 \)
  • Equation: \( y = -0.5(x – 2.9) + 1.65 \)
  • At \( x = 3 \): \( y = -0.5(0.1) + 1.65 = 1.6 \)
4. Conclusion: The limit exists and equals 1.6.
✅ Answer: A) 1.6
Question

Let \( f \) be the piecewise function defined below. Also shown is a portion of the graph of \( f \). What is the value of \( \lim_{x \rightarrow 2} f(f(x)) \)?

\( f(x) = \begin{cases} -x^2 + 3x + 3 & \text{for } x < 2 \\ 6 & \text{for } x = 2 \\ 6 – \frac{1}{2}x & \text{for } x > 2 \end{cases} \)

 

 

 

 

 

 

A) -15

B) -7

C) 3

D) \( \frac{7}{2} \)

▶️ Answer/Explanation
Solution
1. Evaluate \( \lim_{x \to 2} f(x) \):
  • Left limit (\( x \to 2^- \)): Use \(-x^2 + 3x + 3\) → \(-4 + 6 + 3 = 5\)
  • Right limit (\( x \to 2^+ \)): Use \(6 – \frac{1}{2}x\) → \(6 – 1 = 5\)
  • Since both limits equal 5, \( \lim_{x \to 2} f(x) = 5 \).
2. Compute \( f(f(x)) \) as \( x \to 2 \):
  • Since \( f(x) \to 5 \) as \( x \to 2 \), evaluate \( f(5) \):
  • For \( x = 5 > 2 \), use \( 6 – \frac{1}{2}x \) → \( 6 – 2.5 = 3.5 = \frac{7}{2} \).
3. Conclusion:
\[ \lim_{x \rightarrow 2} f(f(x)) = f(5) = \frac{7}{2} \]
✅ Answer: D) \( \frac{7}{2} \)
Question

The table above gives selected values for a function \( f \). Based on the data in the table, which of the following could not be the graph of \( f \) on the interval \( 2.9 \leq x \leq 3.1 \)?

\( x \)2.92.952.992.9993.0013.013.053.1
\( f(x) \)3.43.13.0043.000043.000043.0043.13.4

A .Graph A

B Graph B

C Graph C
D Graph D

▶️ Answer/Explanation
Solution
1. Table Analysis:
  • As \( x \) approaches 3 from both sides, \( f(x) \) approaches 3.
  • The values are symmetric around \( x = 3 \), suggesting continuity.
2. Graph Requirements:
  • The correct graph must show \( f(x) \rightarrow 3 \) as \( x \rightarrow 3 \).
  • Graph D shows a jump discontinuity at \( x = 3 \), which contradicts the table data.
3. Conclusion:
Graph D could not represent \( f \) because it violates the limit behavior shown in the table.
✅ Answer: D)
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