If cos(2θ + 54º) = sinθ, 0º<(2θ + 54º)< 90º, then what is the value of ?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 2-√3
Here it is given that,
cos(2θ + 54º) = sinθ
Sin(90 - 2θ - 54º) = sinθ
-2θ + 36 = θ
3θ = 36
θ = 12°
Tan5θ = Tan60 = √3
Cosec 5θ/2 = Cosec30° = 2
Now,
On rationalizing further we get,
= (2 - √3)/(4 - 3)
= (2 - √3).