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MHT CET · Maths · Limits

If \(\lim _{\mathrm{x} \rightarrow 5} \frac{\mathrm{x}^{\mathrm{k}}-5^{\mathrm{k}}}{\mathrm{x}-5}=500\), then the value of \(\mathrm{k}\), where \(\mathrm{k} \in \mathrm{N}\) is

  1. A 5
  2. B 3
  3. C 4
  4. D 6
Verified Solution

Answer & Solution

Correct Answer

(C) 4

Step-by-step Solution

Detailed explanation

\(\begin{aligned} & \lim _{x \rightarrow 5} \frac{x^k-5^k}{x-5}=500 \\ & \therefore(k)(5)^{k-1}=500 \\ & =4(125)=4(5)^3=4(5)^{4-1} \\ & \therefore k=4\end{aligned}\)