SSC CGL 2021 PYQ — Question 69

SSC CGL - 13 Aug 2021 - Shift 3 • Quantitative Aptitude • Q69

If 3sec θ\theta + 4 cos θ\theta - 4 3\sqrt{3} = 0 where θ\theta is an acute angle then the value of θ\theta is:

Show answer & explanation

Correct answer: D

Explanation

The correct answer is option 4 i.e. 30º

Instead of solving this equation we could just use the substitution method and make our life easy,

⇒ θ\theta = 45o

⇒ 3 sec 45o + 4 cos 45o = 4√3

⇒ 3√2 + 4√2 = 5√2

This is not the correct answer.

 ⇒ θ\theta = 60o

⇒ 3 sec 60o + 4 cos 60o = 4√3

⇒ 3(2) + 4(1/2) 

This is not the correct answer.

⇒ θ\theta = 30o

⇒ 3 sec 30o + 4 cos 30o = 4√3

⇒ 3(2/√3) + 4(√3/2)

⇒ 2√3 + 2√3 = 4√3

This is the correct answer.