Domain Rational Sqrt
1. **State the problem:** Find the domain of the function $$h(x) = \sqrt{\frac{1 - x}{x + 1}}$$ which means we need all values of $$x$$ for which the expression under the square root is defined and non-negative.
2. **Set the radicand non-negative:** The expression inside the square root must be $$\geq 0$$.
$$\frac{1 - x}{x + 1} \geq 0$$.
3. **Identify restrictions:** The denominator cannot be zero.
$$x + 1 \neq 0 \Rightarrow x \neq -1$$.
4. **Solve the inequality:** To solve $$\frac{1 - x}{x + 1} \geq 0$$, consider critical points where the numerator or denominator is zero:
- Numerator zero at $$x = 1$$
- Denominator zero at $$x = -1$$
5. **Test intervals:** Split the real line into intervals determined by $$-1$$ and $$1$$:
- For $$x < -1$$: Choose $$x = -2$$, numerator $$1 - (-2) = 3 > 0$$, denominator $$-2 + 1 = -1 < 0$$, so fraction is negative.
- For $$-1 < x < 1$$: Choose $$x = 0$$, numerator $$1 - 0 = 1 > 0$$, denominator $$0 + 1 = 1 > 0$$, fraction is positive.
- For $$x > 1$$: Choose $$x = 2$$, numerator $$1 - 2 = -1 < 0$$, denominator $$2 + 1 = 3 > 0$$, fraction is negative.
6. **Include points if inequality allows:**
- At $$x = 1$$, numerator zero, fraction $$0$$, valid.
- At $$x = -1$$, denominator zero, undefined, exclude.
7. **Conclusion:** The domain is $$-1 < x \leq 1$$.
**Answer:** Option c. $$-1 < x \leq 1$$