1. **State the problem:** Solve the first-order linear differential equation $$y' + 2xy = x$$.
2. **Identify the type and formula:** This is a linear differential equation of the form $$y' + P(x)y = Q(x)$$ where $$P(x) = 2x$$ and $$Q(x) = x$$.
3. **Find the integrating factor (IF):** The integrating factor is given by $$\mu(x) = e^{\int P(x) dx} = e^{\int 2x dx} = e^{x^2}$$.
4. **Multiply the entire differential equation by the integrating factor:**
$$e^{x^2} y' + 2x e^{x^2} y = x e^{x^2}$$
5. **Recognize the left side as the derivative of a product:**
$$\frac{d}{dx} \left(e^{x^2} y\right) = x e^{x^2}$$
6. **Integrate both sides with respect to $$x$$:**
$$\int \frac{d}{dx} \left(e^{x^2} y\right) dx = \int x e^{x^2} dx$$
7. **Simplify the left side:**
$$e^{x^2} y = \int x e^{x^2} dx + C$$
8. **Evaluate the integral on the right:**
Let $$u = x^2$$, then $$du = 2x dx$$ or $$\frac{du}{2} = x dx$$.
So,
$$\int x e^{x^2} dx = \int e^u \frac{du}{2} = \frac{1}{2} \int e^u du = \frac{1}{2} e^u + C = \frac{1}{2} e^{x^2} + C$$
9. **Substitute back:**
$$e^{x^2} y = \frac{1}{2} e^{x^2} + C$$
10. **Solve for $$y$$:**
$$y = \frac{1}{2} + C e^{-x^2}$$
**Final answer:**
$$y = \frac{1}{2} + C e^{-x^2}$$ where $$C$$ is an arbitrary constant.
Linear Differential Fc246C
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