SSC CPO 2020 PYQ — Question 149

The correct answer is Option 4 i.e. 30°.

cos²θ - sin²θ = $\frac{1}{2}$

Let's put θ = 30°

cos²30° - sin²30°

⇒ ${({\sqrt3\over2})}^2$ - $({1\over2})^2$ 

⇒ ${3\over4} - {1\over4}$ = $2\over4$ = $\frac{1}{2}$

Hence, it satisfies the given condition 

So, θ = 30°