SSC CGL 2021 PYQ — Question 72

SSC CGL - 23 Aug 2021 - Shift 2 • Quantitative Aptitude • Q72

If sin2θtan2θ−sin2θ=5\dfrac{sin^2\theta}{tan^2\theta-sin^2\theta}=5 ,  θ is an acute angle, then the value of 24sin2θ−15sec2θ6cosec2θ−7cot2θ\dfrac{24sin^2\theta-15sec^2\theta}{6cosec^2\theta-7cot^2\theta} is:

Show answer & explanation

Correct answer: C

Explanation

The correct answer is option 3 i.e. -14

⇒ sin2θ\theta/(tan2θ\theta - sin2θ\theta) = 5

⇒ sin2θ\theta × cos2θ\theta/(sin2θ\theta(1 - cos2θ\theta)) = 5

⇒ cot2θ\theta = 5

cotθ\theta = 5\sqrt5 = b/p

By using pythagoras theorem,

H2 = 5 + 1

H = 6\sqrt6

⇒ (24 × 1/6 - 15 × 6/5)/(6 × 6 - 7 × 5)

⇒ (4 - 18)/(1)

= -14.