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\(\displaystyle\lim_{x \to 2} \frac{(x^{3} - 8)\sin(x - 2)}{x^{2} - 4x + 4}\) is equal to

  • A.4
  • B.8
  • C.12
  • D.-8
  • E.-12

Answer: C

The limit is 12.

Factor the numerator and denominator: \(x^{3} - 8 = (x - 2)(x^{2} + 2x + 4)\) and \(x^{2} - 4x + 4 = (x - 2)^{2}\). Then

\[ \begin{aligned} \frac{(x^{3} - 8)\sin(x - 2)}{(x - 2)^{2}} &= (x^{2} + 2x + 4)\frac{\sin(x - 2)}{x - 2} \\ &\to 12 \times 1 = 12 \end{aligned} \]

8 and 4 use only part of \(x^{2} + 2x + 4\) at \(x = 2\), and the negative values come from a sign slip.

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