Railways PYQCBT 1 2020

RRB NTPC · Question 18

If \(\frac{1}{\sin^265^\circ+\cos^265^\circ}+\frac{\sin15^\circ}{\cos75^\circ}+\frac{\cos65^\circ}{\sin25^\circ}=\sqrt{3}tanθ\), then the value of θ is:

  1. 45°

  2. 60°

  3. 90°

  4. 30°

Show answer & explanation

Answer: (B) 60°

Explanation

sin²65° + cos²65° = 1, so the first term is 1. sin 15° = cos 75° and cos 65° = sin 25°, so the other terms are 1 each. Total = 3 = √3 tan θ, so tan θ = √3 and θ = 60°.