NDA2025MathematicsInverse Trigonometric FunctionsActual
What is ⁻¹ 9 + cosec ⁻¹ ( 41 4 ) equal to?
Options
- A4
- B3
- C2
Correct answer
A. 4
Step-by-step solution
Let A = ⁻¹ 9 A = 9 A = 1 9 Let B = cosec ⁻¹ ( 41 4 ) cosec B = 41 4 B = 4 41 From this, B = 4 ( 41 )^2 - 4^2 = 4 41 - 16 = 4 5 Using the formula (A + B) = A + B 1 - A B : (A + B) = 1 9 + 4 5 1 - ( 1 9 ) ( 4 5 ) (A + B) = 5 + 36 45 45 - 4 45 (A + B) = 41 41 = 1 Since A, B (0, 2 ) , we have A + B = 4 Answer: 4