SSC CHSL 2022 PYQ — Question 70

SSC CHSL - 3 June 2022 - Shift 1 • Quantitative Aptitude • Q70

If cosec θ + cot θ = 5, then cosec θ is equal to _________.

Show answer & explanation

Correct answer: C

Explanation

The correct answer is option 3 i.e.  12(5+15)\frac{1}{2}(5+\frac{1}{5})

Given:

cosec θ + cot θ = 5    ..(i)

Formula Used:

cosec2θ - cot2θ = 1

Explanation:

cosec2θ - cot2θ = 1

⇒ (cosecθ + cotθ)(cosecθ - cotθ) = 1

According to the given question,

⇒ 5(cosecθ - cotθ) = 1

⇒ (cosecθ - cotθ) = 151 \over 5   ....(ii)

Now, adding equation (i) and equation(ii), we get

2 cosec θ = 5 + 151 \over 5

⇒ cosec θ = 12(5+15)\frac{1}{2}(5+\frac{1}{5})

Hence the required answer is 12(5+15)\frac{1}{2}(5+\frac{1}{5}).