JEE Main
- Exam
- JEE Main
- Subject
- Mathematics
- Chapter
- Inverse Trigonometric Functions
JEE Main · Mathematics · Inverse Trigonometric Functions
Let f (x) = cosec ^ - 1 [1 + ^ 2 x], ~where~ [·]denotes the...
Let ~where~ \left[\cdot\right]denotes the greatest integer function. Then
Options
- A\left\{\dfrac{π}{2}\right\}
- B\left\{\dfrac{π}{2}, {cosec}^{- 1}2\right\}
- C\left\{{cosec}^{- 1}2\right\}
- DNone of these
Correct answer
B. \left\{\dfrac{π}{2}, {cosec}^{- 1}2\right\}
Step-by-step solution
Given,
f \left(x\right) = {cosec}^{- 1} \left[1 + \sin^{2}x\right],- 1 ≤ \sin x ≤ 1⇒ 0 x ≤ 1⇒ 1 ≤ 1 + \sin^{2}x ≤ 2⇒ \left[1 + \sin^{2}x\right] = 1, 1\le \sin^{2}~and
\left[1 + \sin^{2}x\right] = 2, if2 \le 1 + \sin^{2}x < 3f \left(x\right) = {cosec}^{- 1} \left(1\right)
f\left(x\right) =\dfrac{π}{2}
And,
f \left(x\right) = {cosec}^{- 1}2⇒ f\left(x\right) = {cosec}^{- 1}2</p><p>Therefore,~f\left(x\right)