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Find the value of cot⁡x−tan⁡xcot⁡2x\frac{\cot x - \tan x}{\cot 2x}cot2xcotx−tanx​​ is?
Question

Find the value of cotxtanxcot2x\frac{\cot x - \tan x}{\cot 2x}​ is?

A.

2

B.

1

C.

-1

D.

4

Correct option is A

Given:

cotxtanxcot2x\frac{\cot x - \tan x}{\cot 2x}

Formula used:

cotx=cosxsinx\cot x = \frac{\cos x}{\sin x}

tanx=sinxcosx\tan x = \frac{\sin x}{\cos x}

​​​​sin2x=2sinxcosx\sin2x = 2 \sin x \cos x

cos2xsin2x=cos2x{\cos^2 x - \sin^2 x} = \cos2x​​

Solution:

cotxtanxcot2x\frac{\cot x - \tan x}{\cot 2x}

 (cosxsinxsinxcosx)(cos2xsinx2)\frac{\left( \frac{\cos x}{\sin x} - \frac{\sin x}{\cos x}\right)}{\left( \frac{\cos 2x}{\sin x2}\right)}

(cos2xsin2xsinxcosx)(cos2xsinx2)\frac{\left( \frac{\cos^2 x - \sin^2 x}{\sin x \cos x}\right)}{\left( \frac{\cos 2x}{\sin x2}\right)}​​  

= ​​(cos2xsinxcosx)×(sin2xcos2x){\left( \frac{\cos2x}{\sin x \cos x}\right)}\times{\left( \frac{\sin 2x}{\cos 2x}\right)}

sin2xsinxcosx \frac{\sin 2x}{\sin x \cos x}

2sinxcosxsinxcosx \frac{2\sin x \cos x}{\sin x \cos x}

= 2

Thus, the correct answer is (a).

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