Logarithmic Derivative C43766
1. **State the problem:** Find the derivative of the function $$y = x^{3x}$$ using logarithmic differentiation.
2. **Recall the formula and rules:** For functions of the form $$y = f(x)^{g(x)}$$, logarithmic differentiation is useful. We take the natural logarithm of both sides:
$$\ln y = g(x) \ln f(x)$$
Then differentiate implicitly using the product rule and chain rule.
3. **Apply logarithmic differentiation:**
Take natural log of both sides:
$$\ln y = 3x \ln x$$
4. **Differentiate both sides with respect to $$x$$:**
Using implicit differentiation:
$$\frac{1}{y} \frac{dy}{dx} = 3 \ln x + 3x \cdot \frac{1}{x} = 3 \ln x + 3$$
5. **Solve for $$\frac{dy}{dx}$$:**
Multiply both sides by $$y$$:
$$\frac{dy}{dx} = y (3 \ln x + 3)$$
Recall that $$y = x^{3x}$$, so:
$$\frac{dy}{dx} = x^{3x} (3 \ln x + 3) = 3 x^{3x} (\ln x + 1)$$
**Final answer:**
$$y' = 3 x^{3x} (\ln x + 1)$$