SSC CHSL 2024 PYQ — Question 71

SSC CHSL - 11 July 2024 - Shift 1 • Quantitative Aptitude • Q71

The value of (sinθ1+cosθ+1+cosθsinθ)\left(\frac{sin\theta}{1+cos\theta}+\frac{1+cos\theta}{sin\theta}\right) (1tanθ+cotθ)\left(\frac{1}{tan\theta + cot\theta}\right) is equal to:

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Correct answer: C

Explanation

The correct answer is option 3 i.e. 2 cosθcos\theta.

(sinθ1+cosθ+1+cosθsinθ)(1tanθ+cotθ)\left(\frac{sin\theta}{1+cos\theta}+\frac{1+cos\theta}{sin\theta}\right)\left(\frac{1}{tan\theta + cot\theta}\right)

=(sin2θ+(1+cosθ)2sinθ(1+cosθ))(1sinθcosθ+cosθsinθ)=\left(\frac{sin^2\theta + (1+cos\theta)^2}{sin\theta(1+cos\theta)} \right)\left(\frac{1}{\frac{sin\theta}{cos\theta} + \frac{cos\theta}{sin\theta}}\right)

=(sin2θ+1+2cosθ+cos2θsinθ(1+cosθ))(1sin2θ+cos2θsinθcosθ)=\left(\frac{sin^2\theta + 1 + 2cos\theta + cos^2\theta}{sin\theta(1+cos\theta)}\right)\left(\frac{1}{\frac{sin^2\theta + cos^2\theta}{sin\theta cos\theta}}\right)

=(1+1+2cosθsinθ(1+cosθ))(11sinθcosθ)=\left(\frac{1 + 1 + 2cos\theta}{sin\theta(1+cos\theta)}\right)\left(\frac{1}{\frac{1}{sin\theta cos\theta}}\right)

=(2(1+cosθsinθ(1+cosθ))(sinθcosθ)=\left(\frac{2(1 + cos\theta}{sin\theta(1+cos\theta)}\right)\left(sin\theta cos\theta\right)

= (2/sinθ)(sinθ cosθ)

= 2cosθ

Therefore, the value of the expression is 2cosθ.