AP Calculus BC : 1.11 Defining Continuity at a Point- Exam Style questions with Answer- MCQ

Question

If \(\lim_{x\rightarrow 6}f(x)\) exists with \(\lim_{x\rightarrow 6}f(x)< 8\) and f(6)=12 , which of the following statements must be false?

A \(\lim_{x\rightarrow 6^{-}}f(x)=0\)

B \(\lim_{x\rightarrow 6^{+}}f(x)< 8\)

C \(\lim_{x\rightarrow 6^{-}}f(x)=\lim_{x\rightarrow 6^{+}}f(x)\)

D f is continuous at x=6.

Answer/Explanation

Ans:D

Since \(\lim_{x\rightarrow 6}f(x)< 8\) and f(6)=12. It is false that \( \lim_{x\rightarrow 6}f(x)=6f(x)\) .Therefore,

f

cannot be continuous at 

x=6

.

Question

Let f be the function defined above. Which of the following statements is true?

A f is continuous at x=1.

B f is not continuous at x=1 because f(1) does not exist.

C f is not continuous at x=1 because \(\lim_{x\rightarrow 1^{-}}f(x)\neq \lim_{x\rightarrow 1^{+}}f(x)\).

D f is not continuous at x=1 because \(\lim_{x\rightarrow 1}f(x)\) does not exist.

Answer/Explanation

Ans:B

 

Question

Which of the following functions is continuous at

x=3

 ?

B

C

D

Answer/Explanation

Ans:C

Question 

 For what value of h is continuous at \(x=\frac{5}{2}\) ?

(A) 0
(B) 3
(C) \(x=\frac{25}{2}\)
(D) \(x=\frac{19}{2}\)

Answer/Explanation

Ans:(D)

Since \(\lim_{x\rightarrow \frac{5}{2}}\frac{6x^{2}-11x-10}{2x-5}=\lim_{x\rightarrow \frac{5}{2}}\frac{(2x-5)(3x+2)}{2x-5}=\lim_{x\rightarrow \frac{5}{2}}3x+2=\frac{19}{2}\)

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