Correct Answer - Option 3 : 5/√3
Given :
sec(2θ + 40°) = cosec(3θ)
Formula used :
sec(90° - θ) = cosecθ
Calculations :
sec(2θ + 40°) = cosec(3θ)
sec(2θ + 40°) = sec(90° - 3θ)
Now
2θ + 40° = 90° - 3θ
5θ = 50°
θ = 10°
So,
sec3θ + tan6θ = sec30° + tan60°
⇒ (2/√3) + √3
⇒ 5/√3
∴ Option 3 is the right choice.