SSC CGL 2019 PYQ — Question 59

SSC CGL - 4th June 2019 - Shift 2 • Quantitative Aptitude • Q59

If cos θ = 2p/(1 + p2), then tan θ is equal to:

Show answer & explanation

Correct answer: C

Explanation

Correct Answer is option 3 i.e. (1-p2)/2p

Concept

Understanding

Application

tan x = perpendicular/base

Cos x = base/ hypotenuses

Pythagoras theorem 

Base2 = Hypotenuses2 – Perpendicular2 

Given 

Cos θ = 2p/(1+p2)

By comparing 

base = 2p 

Hypotenuses = (p2+1)

Perpendicular2 = Hypotenuses2 – Base2 = (p2+1)2 - (2p)2

= p4 + 1 + 2p2 – 4p2

= p4 + 1 - 2p2

= (1-p2)2

Perpendicular = (1-p2)

Hence,

Tan θ = (1-p2)/2p