Find the domain of each of the following functions:
(i) `f(x)=sin^(-1)sqrt(x^2-1)`
(ii) `f(x)=sin^(-1)x+sin^(-1)2x`

Explanation

To find the domain of the given functions, we will analyze each function step by step.

### (i) \( f(x) = \sin^{-1}(\sqrt{x^2 - 1}) \)

**Step 1: Determine the condition for the square root.**

The expression inside the square root, \( x^2 - 1 \), must be non-negative for the square root to be defined:
\[
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