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SSC CHSL 2019 PYQ — Question 69

SSC CHSL - 8th July 2019 - Shift 1 • Quantitative Aptitude • Q69

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If cosecθ = 3x and cotθ = 3/x, (x ≠ 0) then the value of 6(x2 - 1/x2) is:

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Correct answer: D

Explanation

Correct answer is option 4 i.e. 2/3

Understanding

Application

cosec2θ – cot2θ = 1

Given

cosecθ = 3x

⇒ x = cosecθ/3 ----(I)

cotθ = 3/x

⇒ x = 3/cotθ ----(II)

From equation (I) and (II):

⇒ cosecθ/3 = 3/cotθ

Now,

6(x2 - 1/x2)

= 6[(cosec2θ/9) - (cot2θ/9)]

= 6[cosec2θ – cot2θ]/9

= 6/9 = 2/3