NTA Abhyas JEE Main2020MathematicsInverse Trigonometric FunctionsPractice
If f x = t a n - 1 x 2 + 4 x + s i n - 1 x 2 + 4 x + 1 , then
Options
- Adomain of f x contains 3 integers only
- Brange of f x has two elements only
- Cf x is a constant function ∀ x ∈ R
- Df x contains only two elements in its domain
Correct answer
D. f x contains only two elements in its domain
Step-by-step solution
∵   x 2 + 4 x ≥ 0 for the first term and 0 ≤ x 2 + 4 x + 1 ≤ 1 for the second term ∴ by both the results, there is only one possibility x 2 + 4 x = 0 ⇒ x = 0 , - 4 ∴   f x = tan - 1 ⁡ 0 + sin - 1 ⁡ 1 = π 2