Root Domains F98162
1. **State the problem:** Find the domains of the functions $$f(x) = \sqrt[4]{x - 9}$$ and $$g(x) = \sqrt[3]{3x - 9}$$ and express them in interval notation.
2. **Recall domain rules for roots:**
- For an even root (like the 4th root), the radicand (expression inside the root) must be \(\geq 0\) because even roots of negative numbers are not real.
- For an odd root (like the cube root), the radicand can be any real number because odd roots of negative numbers are defined.
3. **Find domain of $$f(x)$$:**
- Since $$f(x) = \sqrt[4]{x - 9}$$ is a 4th root, require:
$$x - 9 \geq 0$$
- Solve inequality:
$$x \geq 9$$
- So the domain of $$f$$ is all real numbers from 9 to infinity, including 9.
- In interval notation: $$[9, \infty)$$
4. **Find domain of $$g(x)$$:**
- Since $$g(x) = \sqrt[3]{3x - 9}$$ is a cube root, the radicand can be any real number.
- So no restrictions on $$x$$.
- Domain of $$g$$ is all real numbers.
- In interval notation: $$(-\infty, \infty)$$
**Final answers:**
- Domain of $$f$$: $$[9, \infty)$$
- Domain of $$g$$: $$(-\infty, \infty)$$