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If cot x = 3, then what will be the value of (3+3sin⁡x)(1−sin⁡x)(2+2cos⁡x)(3−3cos⁡x)\frac{(3 + 3 \sin x)(1 - \sin{x})}{(2 + 2 \cos{x})(3 - 3 \cos
Question

If cot x = 3, then what will be the value of (3+3sinx)(1sinx)(2+2cosx)(33cosx)\frac{(3 + 3 \sin x)(1 - \sin{x})}{(2 + 2 \cos{x})(3 - 3 \cos{x})}?​

A.

9

B.

92\frac{9}{2}​​

C.

93\frac{9}{3}​​

D.

94\frac{9}{4}​​

Correct option is B

Given:

cot x = 3

Formula used:

A2B2=(A+B)(AB)Cotθ=CosθSinθ\begin{aligned}& \mathrm{A}^2-\mathrm{B}^2=(\mathrm{A}+\mathrm{B})(\mathrm{A}-\mathrm{B}) \\& \operatorname{Cot} \theta=\frac{\operatorname{Cos} \theta}{\operatorname{Sin} \theta}\end{aligned}

Solution:

(3+3sinx)(1sinx)(2+2cosx)(33cosx)=>3×(1+sinx)(1sinx)6×(1+cosx)(1cosx)=>(1sin2x)2×(1cos2x)=>cos2x2×sin2x=>cot2x2=>322=>92\begin{aligned}& \frac{(3+3 \sin \mathrm{x})(1-\sin \mathrm{x})}{(2+2 \cos \mathrm{x})(3-3 \cos \mathrm{x})} \\\Rightarrow & \frac{3 \times(1+\sin x)(1-\sin x)}{6 \times(1+\cos x)(1-\cos x)} \\\Rightarrow & \frac{\left(1-\sin ^2 x\right)}{2 \times\left(1-\cos ^2 x\right)} \\\Rightarrow & \frac{\cos ^2 x}{2 \times \sin ^2 x} \\\Rightarrow & \frac{\cot ^2 x}{2} \\\Rightarrow & \frac{3^2}{2} \\\Rightarrow & \frac{9}{2}\end{aligned} 

Thus, the correct answer is option (b).

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