SSC CHSL 2019 PYQ — Question 60

SSC CHSL - 1st July 2019 - Shift 3 • Quantitative Aptitude • Q60

cot θ/[(1 – sin θ) (sec θ + tan θ)] is equal to:

Show answer & explanation

Correct answer: B

Explanation

The Correct Answer is option 2 i.e. cosecθ.

tanθ = sinθ/cosθ

cotθ = cosθ/sinθ

secθ = 1/cosθ

1- sin2θ = cos2θ

Use these values in the given expression

⇒ cotθ(1−sinθ)(secθ+tanθ){cot\theta}\over(1-sin\theta)(sec\theta+tan\theta)

⇒ cotθ(1−sinθ)(1cosθ+sinθcosθ){cot\theta}\over{{(1-sin\theta)}{({1\over cos\theta}}+{sin\theta \over cos\theta}})

 ⇒ cotθ(1−sinθ)(1−sinθcosθ){cot\theta}\over{{(1-sin\theta)}({1-sin\theta \over cos\theta}})

 ⇒ cosθsinθcosθ(1−sin2θ){{cos\theta}\over sin\theta}{{{cos\theta}\over({1-sin^2\theta})}}

 ⇒ cos2θsinθcos2θ{{cos^2\theta}\over sin\theta cos^2\theta}

 ⇒ 1sinθ=cosecθ{1\over sin\theta} = cosec\theta