Step 1: Formula / Definition}
\[
\sin^{-1}\left(\frac{2x}{1+x^2}\right) = \begin{cases} 2\tan^{-1}x, & |x| \leq 1 \\ \pi - 2\tan^{-1}x, & x>1 \\ -\pi - 2\tan^{-1}x, & x<-1 \end{cases}
\]
Step 2: Calculation / Simplification}
For \(|x| \leq 1\): \(2\tan^{-1}x + 2\tan^{-1}x = 4\tan^{-1}x\) (depends on \(x\))
For \(|x|>1\): \(2\tan^{-1}x + (\pi - 2\tan^{-1}x) = \pi\) (constant)
\(\therefore\) Independent of \(x\) when \(|x|>1\).
Step 3: Final Answer
\[
|x|>1
\]