Question: User: $$\oint x dx$$
1. **Problem Statement:** Evaluate the line integral $$\oint x \, dx$$ over a closed curve.
2. **Understanding the Integral:** The symbol $$\oint$$ denotes a line integral over a closed path. Here, the integrand is $$x$$ with respect to $$dx$$.
3. **Key Rule:** For any closed curve, the integral of an exact differential over that curve is zero. Since $$x \, dx$$ is an exact differential of $$\frac{x^2}{2}$$, the integral over a closed path is zero.
4. **Mathematical Explanation:**
$$\oint x \, dx = \oint d\left(\frac{x^2}{2}\right) = 0$$
because the integral of an exact differential over a closed loop is zero.
5. **Final Answer:**
$$\boxed{0}$$