Derivative Domain Log Root
1. **Problem:** Find the derivative and domain of the function $$f(x) = \sqrt{4 + \ln(x)}$$ and analyze related domain conditions for $$g(x) = \ln(x^2 - 12x)$$.
2. **Derivative of** $$f(x)$$:
Given $$f(x) = \sqrt{4 + \ln(x)} = (4 + \ln(x))^{1/2}$$.
Use the chain rule:
$$f'(x) = \frac{1}{2}(4 + \ln(x))^{-1/2} \cdot \frac{d}{dx}(4 + \ln(x))$$
Since $$\frac{d}{dx}(4 + \ln(x)) = \frac{1}{x}$$,
therefore,
$$f'(x) = \frac{1}{2\sqrt{4 + \ln(x)}} \cdot \frac{1}{x} = \frac{1}{2x\sqrt{4 + \ln(x)}}$$.
3. **Domain of** $$f(x)$$:
The expression inside the square root must be non-negative:
$$4 + \ln(x) \geq 0 \Rightarrow \ln(x) \geq -4$$
Exponentiate both sides:
$$x \geq e^{-4}$$
Also, since $$\ln(x)$$ requires $$x > 0$$,
final domain is:
$$\boxed{[e^{-4}, \infty)}$$.
4. **Domain of** $$g(x) = \ln(x^2 - 12x)$$:
Inside the logarithm, the argument must be positive:
$$x^2 - 12x > 0$$
Factor:
$$x(x - 12) > 0$$
Using sign analysis,
- For $$x < 0$$, both factors $$x$$ and $$x - 12$$ have opposite signs: $$x < 0$$ and $$x - 12 < 0$$ gives positive product since negative * negative = positive.
- For $$0 < x < 12$$ product is negative.
- For $$x > 12$$ product is positive.
Thus, domain of $$g(x)$$ is:
$$(-\infty, 0) \cup (12, \infty)$$.
5. **Final answers:**
- Derivative of $$f(x)$$:
$$f'(x) = \frac{1}{2x\sqrt{4 + \ln(x)}}$$
- Domain of $$f(x)$$:
$$[e^{-4}, \infty)$$
- Domain of $$g(x)$$:
$$(-\infty, 0) \cup (12, \infty)$$