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Solve the differential equation: x (dy...

Solve the differential equation:
`x (dy)/(dx)+y=3x^(2)-2`

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To solve the differential equation \( x \frac{dy}{dx} + y = 3x^2 - 2 \), we will follow these steps: ### Step 1: Rewrite the equation We start with the given differential equation: \[ x \frac{dy}{dx} + y = 3x^2 - 2 \] To simplify, we divide the entire equation by \( x \): \[ \frac{dy}{dx} + \frac{1}{x} y = \frac{3x^2 - 2}{x} \] This simplifies to: \[ \frac{dy}{dx} + \frac{1}{x} y = 3x - \frac{2}{x} \] **Hint:** Dividing by \( x \) helps to isolate \( \frac{dy}{dx} \) and makes it easier to identify the linear form. ### Step 2: Identify the integrating factor The standard form of a linear differential equation is: \[ \frac{dy}{dx} + P(x) y = Q(x) \] where \( P(x) = \frac{1}{x} \) and \( Q(x) = 3x - \frac{2}{x} \). The integrating factor \( \mu(x) \) is given by: \[ \mu(x) = e^{\int P(x) \, dx} = e^{\int \frac{1}{x} \, dx} = e^{\ln |x|} = |x| \] Since \( x > 0 \) in our context, we can simply use \( \mu(x) = x \). **Hint:** The integrating factor is crucial for solving linear differential equations, as it allows us to combine terms into a single derivative. ### Step 3: Multiply through by the integrating factor Now we multiply the entire differential equation by the integrating factor \( x \): \[ x \frac{dy}{dx} + y = x(3x - \frac{2}{x}) \] This simplifies to: \[ x \frac{dy}{dx} + y = 3x^2 - 2 \] Notice that the left-hand side can be expressed as the derivative of a product: \[ \frac{d}{dx}(xy) = 3x^2 - 2 \] **Hint:** Recognizing the left side as a derivative of a product simplifies the integration process. ### Step 4: Integrate both sides Now we integrate both sides with respect to \( x \): \[ \int \frac{d}{dx}(xy) \, dx = \int (3x^2 - 2) \, dx \] This gives us: \[ xy = x^3 - 2x + C \] where \( C \) is the constant of integration. **Hint:** When integrating, remember to add the constant of integration, as it represents the family of solutions. ### Step 5: Solve for \( y \) Now, we can solve for \( y \): \[ y = \frac{x^3 - 2x + C}{x} \] This simplifies to: \[ y = x^2 - 2 + \frac{C}{x} \] **Hint:** Isolating \( y \) gives us the final form of the solution, which can include a term that approaches zero as \( x \) increases. ### Final Answer Thus, the general solution to the differential equation is: \[ y = x^2 - 2 + \frac{C}{x} \]
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