Home / AP Calculus BC : 1.4 Estimating Limit  Values from Tables- Exam Style questions with Answer- MCQ

AP Calculus BC : 1.4 Estimating Limit  Values from Tables- Exam Style questions with Answer- MCQ

Question

The table below gives values of the function \( f \) at selected values of \( x \). Which of the following statements must be true?

\( x \)1.91.991.9991.999922.00012.0012.012.1
\( f(x) \)7.807.867.907.9538.058.108.148.20

A) \(\lim_{x \to 2} f(x)=3\)

B) \(\lim_{x \to 2} f(x)=8\)

C) \(\lim_{x \to 2} f(x)\) does not exist.

D) \(\lim_{x \to 2} f(x)\) cannot be definitively determined from the data in the table.

▶️ Answer/Explanation
Solution
1. Left-hand limit (approaching 2 from below):
As \( x \) approaches 2 from the left (\( x \to 2^- \)), \( f(x) \) approaches approximately 8.
Values: 7.80, 7.86, 7.90, 7.95

2. Right-hand limit (approaching 2 from above):
As \( x \) approaches 2 from the right (\( x \to 2^+ \)), \( f(x) \) approaches approximately 8.
Values: 8.05, 8.10, 8.14, 8.20

3. Function value at x=2:
\( f(2) = 3 \) (which is different from the limit values)

4. Conclusion:
– The left and right limits both approach 8, suggesting \(\lim_{x \to 2} f(x) = 8\)
– However, the function value at x=2 is different (3)
– The table doesn’t show values arbitrarily close to 2, so we cannot be certain about the limit
– Therefore, the limit cannot be definitively determined from the given data
✅ Answer: D) \(\lim_{x \to 2} f(x)\) cannot be definitively determined from the data in the table.
Question

The table below gives values of a function \( f \) at selected values of \( x \). Which of the following conclusions is supported by the data in the table?

\( x \)4.94.994.9994.99995.00015.0015.015.1
\( f(x) \)4-16-256-7267.99997.9997.997.9

A) \(\lim_{x \to 5} f(x)=8\)

B) \(\lim_{x \to 5^-} f(x)=8\)

C) \(\lim_{x \to 5^+} f(x)=8\)

D) \(\lim_{x \to 8^+} f(x)=5\)

▶️ Answer/Explanation
Solution
1. Left-hand limit (approaching 5 from below):
As \( x \) approaches 5 from the left (\( x \to 5^- \)), \( f(x) \) becomes increasingly negative:
Values: 4, -16, -256, -726 (no approach to 8)

2. Right-hand limit (approaching 5 from above):
As \( x \) approaches 5 from the right (\( x \to 5^+ \)), \( f(x) \) approaches 8:
Values: 7.9999, 7.999, 7.99, 7.9 (clearly approaching 8)

3. Two-sided limit:
Since the left-hand and right-hand limits are different, \(\lim_{x \to 5} f(x)\) does not exist

4. Option analysis:
– A) False (two-sided limit doesn’t exist)
– B) False (left-hand limit doesn’t approach 8)
– C) True (right-hand limit clearly approaches 8)
– D) False (irrelevant to the data shown)
✅ Answer: C) \(\lim_{x \to 5^+} f(x)=8\)
Question

The table below gives selected values for a continuous function \( f \). Based on the data in the table, which of the following is the best approximation for \(\lim_{x \to 4} f(x)\)?

\( x \)3.93.993.9994.0014.014.1
\( f(x) \)7.0187.0077.0026.9985.9825.887

A) 0

B) 4

C) 7

D) There is no best approximation, because the limit does not exist.

▶️ Answer/Explanation
Solution
1. Left-hand limit (approaching 4 from below):
As \( x \) approaches 4 from the left (\( x \to 4^- \)), \( f(x) \) approaches approximately 7:
Values: 7.018, 7.007, 7.002 (clearly approaching 7)

2. Right-hand limit (approaching 4 from above):
For values very close to 4 from the right (4.001), \( f(x) = 6.998 \) (still close to 7)

3. Best approximation:
– The immediate values closest to 4 (3.999 and 4.001) show \( f(x) \) approaching 7
– The function is stated to be continuous
4. Conclusion:
The best approximation for \(\lim_{x \to 4} f(x)\) is 7
✅ Answer: C) 7
Question

Find the limit: \(\lim_{t\rightarrow -3}\frac{t+3}{t^{2}+9}\)

A) \(-\frac{1}{3}\)

B) 0

C) \(\frac{1}{3}\)

D) 1

▶️ Answer/Explanation
Solution
1. Direct Substitution:
\[ \frac{(-3)+3}{(-3)^2+9} = \frac{0}{9+9} = \frac{0}{18} = 0 \]
Since we don’t get an indeterminate form (like 0/0), direct substitution works.
2. Analysis:
– Numerator approaches 0 as t → -3
– Denominator approaches 18 as t → -3 (never zero)
– Therefore, the limit is 0/18 = 0
✅ Answer: B) 0
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