Solve Differential 826C9B
1. **State the problem:** Solve the differential equation $\left(x^2D^2 + xD\right)y = 0$, where $D = \frac{d}{dx}$.
2. **Rewrite the equation:** The operator $D$ represents differentiation with respect to $x$. So the equation is:
$$x^2 \frac{d^2y}{dx^2} + x \frac{dy}{dx} = 0$$
3. **Divide through by $x$ (assuming $x \neq 0$):**
$$x \frac{d^2y}{dx^2} + \frac{dy}{dx} = 0$$
4. **Let $p = \frac{dy}{dx}$, then $\frac{d^2y}{dx^2} = \frac{dp}{dx}$:**
$$x \frac{dp}{dx} + p = 0$$
5. **This is a first-order linear ODE in $p$: **
$$x \frac{dp}{dx} = -p$$
6. **Rewrite as:**
$$\frac{dp}{dx} = -\frac{p}{x}$$
7. **Separate variables:**
$$\frac{dp}{p} = -\frac{dx}{x}$$
8. **Integrate both sides:**
$$\int \frac{1}{p} dp = -\int \frac{1}{x} dx$$
$$\ln|p| = -\ln|x| + C_1$$
9. **Exponentiate:**
$$|p| = e^{C_1} \frac{1}{|x|}$$
Let $C = e^{C_1}$, so
$$p = \frac{C}{x}$$
10. **Recall $p = \frac{dy}{dx}$, so:**
$$\frac{dy}{dx} = \frac{C}{x}$$
11. **Integrate again:**
$$y = C \int \frac{1}{x} dx = C \ln|x| + C_2$$
12. **General solution:**
$$y = C_1 \ln|x| + C_2$$
**Answer:** The general solution to the differential equation is
$$y = C_1 \ln|x| + C_2$$