Radical Domains 945C23
1. **State the problem:** Find the domains of the functions $$f(x) = \sqrt[4]{x} - 9$$ and $$g(x) = \sqrt[3]{3x} - 9$$ and write the answers in interval notation.
2. **Recall domain rules for radicals:**
- For an even root function like the fourth root $$\sqrt[4]{x}$$, the radicand (expression inside the root) must be \(\geq 0\) because even roots of negative numbers are not real.
- For an odd root function like the cube root $$\sqrt[3]{3x}$$, the radicand can be any real number (no restriction).
3. **Find domain of $$f(x)$$:**
- Since $$f(x) = \sqrt[4]{x} - 9$$, the radicand is $$x$$.
- Set $$x \geq 0$$.
- So, domain of $$f$$ is all real numbers $$x$$ such that $$x \geq 0$$.
- In interval notation: $$[0, \infty)$$.
4. **Find domain of $$g(x)$$:**
- Since $$g(x) = \sqrt[3]{3x} - 9$$, the radicand is $$3x$$.
- Cube root allows all real numbers, so no restriction on $$3x$$.
- Therefore, domain of $$g$$ is all real numbers $$(-\infty, \infty)$$.
**Final answers:**
- Domain of $$f$$: $$[0, \infty)$$
- Domain of $$g$$: $$(-\infty, \infty)$$