1)

  $\lim_{x \rightarrow 0}\frac{(1-\cos 2x)(3+\cos x)}{x\tan 4x}$   is equal to 


A) - $\frac{1}{4}$

B) $\frac{1}{2}$

C) 1

D) 2

Answer:

Option D

Explanation:

Let I=   $\lim_{x \rightarrow 0}\frac{(1-\cos 2x)}{x^{2}}\frac{(3+\cos x)}{1}.\frac{x}{\tan 4x}$

  = $\lim_{x \rightarrow 0}\frac{2\sin^{2}x}{x^{2}}.\frac{3+\cos x}{1}.\frac{x}{\tan 4x}$

      =  $2\lim_{x \rightarrow 0}\left(\frac{\sin^{}x}{x^{}}\right)^{2}\lim_{x \rightarrow 0}.(3+\cos x).\lim_{x \rightarrow 0}\frac{4x}{4\tan 4x}$

   = $2.(1)^{2}.(3+\cos 0^{o}).\frac{1}{4}(1)$

                  =   $2.1.(3+1).\frac{1}{4}=2.4.\frac{1}{4}=2$