SSC CHSL 2021 PYQ — Question 73

SSC CHSL - 16 April 2021 - Shift 2 • Quantitative Aptitude • Q73

If (cos2θ−1)(2sec2θ)+sec2θ+2tan2θ=2,0°<θ<90°(cos^2\theta-1)(2sec^2\theta) + sec²\theta+2tan^2\theta=2,0° <\theta< 90°, then the value of (secθ+sinθ)(cosecθ−cosθ)\frac{(sec\theta + sin\theta)}{(cosec\theta-cos\theta)} will be:

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Correct answer: C

Explanation

The correct answer is option 3 i.e. 3

(cos2θ−1)(2sec2θ)+sec2θ+2tan2θ=2,0°<θ<90°(cos^2\theta-1)(2sec^2\theta) + sec²\theta+2tan^2\theta=2,0° <\theta< 90°

- sin2θ * 2/cos2θ  + sec2θ + 2tan2θ = 2

- 2 tan2θ + sec2θ + 2tan2θ = 2

sec2θ = 2

sec θ = √2

θ = 45º

Now, (secθ+sinθ)(cosecθ−cosθ)\frac{(sec\theta + sin\theta)}{(cosec\theta-cos\theta)}

(sec 45+sin 45)(cosec 45−cos 45)\frac{(sec\ 45 + sin\ 45)}{(cosec\ 45-cos\ 45)} = 2+(1/2)2−(1/2)\frac{\sqrt2 + (1/\sqrt2)}{\sqrt2-(1/\sqrt2)} = 3