2017 · Q47
If 0 < x < π/2, then (sin x + cosec x) is
Elementary MathematicsTrigonometry
- A> 2
- B< 2
- C≥ 2
- D≤ 2
Explanation
sin x+cosec x = t+1/t with t = sin x ∈ (0,1) for 0 < x < π/2. Since t+1/t ≥ 2 with equality only at t = 1, and t < 1 strictly on this interval, the value strictly exceeds 2. Hence option (A) > 2.