SSC CGL 2019 PYQ — Question 51

SSC CGL - 4th June 2019 - Shift 3 • Quantitative Aptitude • Q51

If sec θ – tan θ = P, then cosec θ = ?

Show answer & explanation

Correct answer: A

Explanation

Correct Answer is option 1 i.e. 

Understanding

Application

Given:

Secθ – Tanθ = P

Sec2θ – Tan2θ = 1

⇒ (Secθ – Tanθ) (Secθ + Tanθ) = 1

                                   Since, Secθ – Tanθ = P

⇒ (Secθ + Tanθ) = 1/P

Adding both equations:

⇒ Secθ = (P + 1/P)/2 

⇒ Secθ = (P2 + 1)/2P

So, Cosθ = 2P/(P2 + 1) = Base/Hypotenuse

Hence,

Perpendicular = (1 – P2)

Cosecθ = Hypotenuse/Perpendicular = (P2 + 1)/(1 – P2)