Question

If cosx = 1 – 2sin²32°, α, β are the value of x between 0° and 360° with α < β then α = ________

(a) 180° – β

(b) 200° – β 

(c) (β/4) – 10° 

(d) (β/5) – 4°

Answer 1

The correct option (c) (β/4) – 10°  

Explanation:

cosx = 1 – 2sin²32 

∴ cosx = cos(2 × 32)

∴ cosx = cos64 

 ∴ x = 64° or  x = 296°

as α < β

∴ α = 64° and β = 296°

∴ α = [(296) / 4] – 10° 

∴ α = (β/4) – 10°.