NTA Abhyas JEE Main2020MathematicsInverse Trigonometric FunctionsPractice
The number of real solutions of cot - 1 x x + 4 + cos - 1 x 2 + 4 x + 1 = π 2 is equal to
Options
- A0
- B1
- C2
- DInfinite
Correct answer
C. 2
Step-by-step solution
Let, f x = cot - 1 x x + 4 + cos - 1 x 2 + 4 x + 1 For f x to be defined, we have x 2 + 4 x ≥ 0 and 0 ≤ x 2 + 4 x + 1 ≤ 1 Which is only possible if x 2 + 4 x = 0 ⇒ x = 0 , - 4 Also these values satisfies the equation ∴ Number of solutions = 2