Solve this following

Question:

Let $f: \mathbf{R} \rightarrow \mathbf{R}$ be a function such that $f(2)=4$ and

$f^{\prime}(2)=1 .$ Then, the value of $\lim _{x \rightarrow 2} \frac{x^{2} f(2)-4 f(x)}{x-2}$ is

equal to :

 

  1. 4

  2. 8

  3. 16

  4. 12


Correct Option: , 4

Solution:

Apply L'Hopital Rule

$\lim _{x \rightarrow 2}\left(\frac{2 x f(2)-4 f^{\prime}(x)}{1}\right)$

$=\frac{4(4)-4}{1}=12$

 

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