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Simplify: 1−sec⁡xcosec⁡x⋅cot⁡x\frac{1 - \sec x}{\cosec x \cdot \cot x}cosecx⋅cotx1−secx​​
Question

Simplify:
1secxcosecxcotx\frac{1 - \sec x}{\cosec x \cdot \cot x}

A.

(cosx+1)cot2x (\cos x +1) \cot^2 x

B.

(cosx+1)tan2x (\cos x + 1) \tan^2 x

C.

(cosx1)tan2x (\cos x - 1) \tan^2 x

D.

(cosx1)cot2x (\cos x - 1) \cot^2 x

Correct option is C

Given
Expression = 1secxcosecxcotx\frac{1 - \sec x}{\cosec x \cdot \cot x}​​

Formula Used
secx=1cosx cscx=1sinx cotx=cosxsinx tanx=sinxcosx \sec x = \frac{1}{\cos x} \\\ \\\csc x = \frac{1}{\sin x} \\\ \\\cot x = \frac{\cos x}{\sin x} \\\ \\\tan x = \frac{\sin x}{\cos x} \\\ \\​​

Solution
Convert all trigonometric terms into sine and cosine.
Numerator = 1secx=11cosx=cosx1cosx 1 - \sec x = 1 - \frac{1}{\cos x} = \frac{\cos x - 1}{\cos x}​​
Denominator = cscxcotx=1sinxcosxsinx=cosxsin2x\csc x \cdot \cot x = \frac{1}{\sin x} \cdot \frac{\cos x}{\sin x} = \frac{\cos x}{\sin^2 x}​​

Expression = cosx1cosxcosxsin2x \frac{\frac{\cos x - 1}{\cos x}}{\frac{\cos x}{\sin^2 x}}​​

Expression = cosx1cosxsin2xcosx\frac{\cos x - 1}{\cos x} \cdot \frac{\sin^2 x}{\cos x}​​

Expression = (cosx1)sin2xcos2x(\cos x - 1) \cdot \frac{\sin^2 x}{\cos^2 x}​​

Since sin2xcos2x=tan2x: \frac{\sin^2 x}{\cos^2 x} = \tan^2 x:​​

Expression =(cosx1)tan2x (\cos x - 1) \tan^2 x​​
Final Answer
So the correct answer is (c)

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