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Question: The given differential equation is: $(x+3y^2)\frac{dy}{dx} = y$...

The given differential equation is: (x+3y2)dydx=y(x+3y^2)\frac{dy}{dx} = y

Answer

The general solution to the differential equation is: x=3y2+Cyx = 3y^2 + Cy

Explanation

Solution

The given differential equation is (x+3y2)dydx=y(x+3y^2)\frac{dy}{dx} = y. To solve this, we can rewrite it as dxdy=x+3y2y\frac{dx}{dy} = \frac{x+3y^2}{y}, which simplifies to dxdy=xy+3y\frac{dx}{dy} = \frac{x}{y} + 3y. Rearranging this into the standard form of a first-order linear differential equation, dxdy+P(y)x=Q(y)\frac{dx}{dy} + P(y)x = Q(y), we get: dxdy1yx=3y\frac{dx}{dy} - \frac{1}{y}x = 3y Here, P(y)=1yP(y) = -\frac{1}{y} and Q(y)=3yQ(y) = 3y.

The integrating factor (IF) is calculated as IF=eP(y)dyIF = e^{\int P(y) dy}. IF=e(1y)dy=elny=elny1=y1IF = e^{\int (-\frac{1}{y}) dy} = e^{-\ln|y|} = e^{\ln|y|^{-1}} = |y|^{-1}. Assuming y0y \neq 0, we take IF=1yIF = \frac{1}{y}.

The general solution is given by xIF=Q(y)IFdy+Cx \cdot IF = \int Q(y) \cdot IF \, dy + C. Substituting the values: x1y=(3y)(1y)dy+Cx \cdot \frac{1}{y} = \int (3y) \cdot \left(\frac{1}{y}\right) dy + C xy=3dy+C\frac{x}{y} = \int 3 \, dy + C xy=3y+C\frac{x}{y} = 3y + C x=y(3y+C)x = y(3y + C) x=3y2+Cyx = 3y^2 + Cy