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dydx=4y\frac{dy}{dx} = -4y, and y=3y=3 when x=2x=2. Solve the equation.

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Q. dydx=4y\frac{dy}{dx} = -4y, and y=3y=3 when x=2x=2. Solve the equation.
  1. Identify Type and Method: Identify the type of differential equation and the method to solve it.\newlineThe given differential equation dydx=4y\frac{dy}{dx} = -4y is a first-order linear homogeneous differential equation. The method to solve such an equation is to find the integrating factor and then integrate both sides.
  2. Solve Differential Equation: Solve the differential equation.\newlineThe general solution to the differential equation dydx=4y\frac{dy}{dx} = -4y can be found by separating variables. We can rewrite the equation as dyy=4dx\frac{dy}{y} = -4 dx and then integrate both sides.
  3. Perform Integration: Perform the integration on both sides.\newline(1y)dy=(4)dx\int(\frac{1}{y}) dy = \int(-4) dx\newlinelny=4x+C\ln|y| = -4x + C, where CC is the constant of integration.
  4. Solve for y: Solve for y.\newlineTo solve for y, we exponentiate both sides of the equation:\newlineelny=e(4x+C)e^{\ln|y|} = e^{(-4x + C)}\newliney=e(4x)eCy = e^{(-4x)} \cdot e^{C}\newlineSince eCe^{C} is just a constant, we can rename it as CC':\newliney=Ce(4x)y = C'e^{(-4x)}
  5. Use Initial Condition: Use the initial condition to find the value of CC'. We are given that y=3y=3 when x=2x=2. We substitute these values into the equation to solve for CC': 3=Ce(42)3 = C'e^{(-4\cdot2)} 3=Ce(8)3 = C'e^{(-8)} C=3e(8)C' = \frac{3}{e^{(-8)}}
  6. Calculate CC' Value: Calculate the value of CC'.C=3e8=3×e8C' = \frac{3}{e^{-8}} = 3 \times e^8
  7. Write Final Solution: Write the final solution with the value of CC'.\newlineThe final solution to the differential equation with the initial condition is:\newliney=(3e8)e4xy = (3 \cdot e^8)e^{-4x}

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