Integral Ln X 32C6D6
1. **State the problem:** We need to evaluate the integral $$\int \frac{\ln x}{2x^3} \, dx$$.
2. **Rewrite the integral:** Express the integral as $$\int \frac{\ln x}{2x^3} \, dx = \frac{1}{2} \int \frac{\ln x}{x^3} \, dx$$.
3. **Use substitution or integration by parts:** Let’s use integration by parts where we set:
- $$u = \ln x$$ so that $$du = \frac{1}{x} dx$$
- $$dv = x^{-3} dx$$ so that $$v = \int x^{-3} dx = \frac{x^{-2}}{-2} = -\frac{1}{2x^2}$$
4. **Apply integration by parts formula:**
$$\int u \, dv = uv - \int v \, du$$
So,
$$\int \frac{\ln x}{x^3} dx = \ln x \cdot \left(-\frac{1}{2x^2}\right) - \int \left(-\frac{1}{2x^2}\right) \cdot \frac{1}{x} dx = -\frac{\ln x}{2x^2} + \frac{1}{2} \int x^{-3} dx$$
5. **Evaluate the remaining integral:**
$$\int x^{-3} dx = \frac{x^{-2}}{-2} = -\frac{1}{2x^2}$$
6. **Substitute back:**
$$-\frac{\ln x}{2x^2} + \frac{1}{2} \left(-\frac{1}{2x^2}\right) + C = -\frac{\ln x}{2x^2} - \frac{1}{4x^2} + C$$
7. **Recall the factor outside the integral:**
The original integral was $$\frac{1}{2} \int \frac{\ln x}{x^3} dx$$, so multiply the result by $$\frac{1}{2}$$:
$$\frac{1}{2} \left(-\frac{\ln x}{2x^2} - \frac{1}{4x^2}\right) + C = -\frac{\ln x}{4x^2} - \frac{1}{8x^2} + C$$
**Final answer:**
$$\int \frac{\ln x}{2x^3} \, dx = -\frac{\ln x}{4x^2} - \frac{1}{8x^2} + C$$