Prove the following

Question:

If $\mathrm{e}^{\left(\cos ^{2} x+\cos ^{4} x+\cos ^{6} x+\ldots \infty\right) \log _{e} 2}$ satisfies the equation $t^{2}-9 t+8=0$, then the value of $\frac{2 \sin x}{\sin x+\sqrt{3} \cos x}\left(0

  1. (1) $\frac{3}{2}$

  2. (2) $2 \sqrt{3}$

  3. (3) $\frac{1}{2}$

  4. (4) $\sqrt{3}$


Correct Option: , 3

Solution:

$\mathbf{e}^{\left(\cos ^{2} x+\cos ^{4} x+\ldots \ldots \infty\right) \ln 2}=2^{\cos ^{2} x+\cos ^{4} x+\ldots \ldots \infty}$

$=2^{\cot ^{2} x}$

$t^{2}-9 t+8=0 \Rightarrow t=1,8$

$\Rightarrow 2^{\cot ^{2} x}=1,8 \Rightarrow \cot ^{2} x=0,3$

$\$ 0 \Rightarrow \frac{2 \sin x}{\sin x+\sqrt{3} \cos x}=\frac{2}{1+\sqrt{3} \cot x}=\frac{2}{4}=\frac{1}{2}$

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