SSC CGL 2021 PYQ — Question 52

SSC CGL - 18 Aug 2021 - Shift 2 • Quantitative Aptitude • Q52

(secθ+tanθ)2+1+cosecθ1−cosecθ(sec \theta + tan \theta) ^2 + \frac{1+cosec\theta }{1-cosec\theta}  00<θ<9000^0 < \theta < 90^0 is:

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Correct answer: A

Explanation

The correct answer is option 1 i.e. 0

⇒ (secθ+tanθ)2+1+cosecθ1−cosecθ(sec \theta + tan \theta) ^2 + \frac{1+cosec\theta }{1-cosec\theta}

⇒ [(1/cosθ\theta) + sinθ\theta/cosθ\theta]2 - cosecθ+1cosecθ−1\frac{cosec\theta + 1 }{cosec\theta - 1}

 ⇒ [(1 + sinθ\theta)/ cosθ\theta]2 - 1+sinθ1−sinθ\frac{1 + sin\theta }{1 - sin\theta}

 ⇒ [(1 + sinθ\theta)/ cosθ\theta]2 - 1+sinθ1−sinθ×1+sinθ1+sinθ\frac{1 + sin\theta }{1 - sin\theta}\times \frac{1 + sin\theta }{1+sin\theta}

 ⇒ [(1 + sinθ\theta)/ cosθ\theta]2 - (1+sinθ)2(1−sin2θ)\frac{(1 + sin\theta)^2 }{(1 - sin^2\theta)}

 ⇒ [(1 + sinθ\theta)/ cosθ\theta]2 - [(1 + sinθ\theta)/ cosθ\theta]2  = 0