Question:medium

The Range of $f(x) = \sin^{-1} \left( \frac{1}{x^2 - 2x + 2} \right)$ is:

Updated On: Apr 3, 2026
  • $(0, \frac{\pi}{2})$
  • $[0, \frac{\pi}{2}]$
  • $(0, \frac{\pi}{2}]$
  • $[0, \frac{\pi}{2})$
Show Solution

The Correct Option is C

Solution and Explanation

Step 1: Understanding the Concept:
To find the range of \( \sin^{-1}(g(x)) \), we first determine the range of the internal function \( g(x) = \frac{1}{x^2 - 2x + 2} \).
Step 2: Key Formula or Approach:
Complete the square for the denominator:
\( x^2 - 2x + 2 = (x - 1)^2 + 1 \).
Let \( D = (x - 1)^2 + 1 \). Since \( (x - 1)^2 \ge 0 \), we have \( D \ge 1 \).
Step 3: Detailed Explanation:
The range of the denominator \( D \) is \( [1, \infty) \).
As \( D \to \infty \), \( \frac{1}{D} \to 0 \).
As \( D = 1 \), \( \frac{1}{D} = 1 \).
Thus, the range of \( \frac{1}{x^2 - 2x + 2} \) is \( (0, 1] \).
Now apply \( \sin^{-1} \):
The minimum value approaches \( \sin^{-1}(0) = 0 \) (not included).
The maximum value is \( \sin^{-1}(1) = \pi/2 \) (included).
Therefore, the range is \( (0, \pi/2] \).
Step 4: Final Answer:
The range of the function is \( (0, \pi/2] \).
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