Find the solution to the initial value problem

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SUMMARY

The solution to the initial value problem dy/dx - y = e^3x with y(0) = 3 involves using the integrating factor method. The integrating factor is I(x) = e^∫-1 = e^-x. The correct manipulation leads to the equation e^-x(dy/dx) - e^-x . y = e^2x, which integrates to yield y = C + 2e^3x. However, the proposed solution does not satisfy the initial condition, indicating a mistake in the calculations.

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  • Understanding of first-order linear differential equations
  • Familiarity with integrating factors in differential equations
  • Knowledge of exponential functions and their properties
  • Ability to perform integration and apply initial conditions
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  • Review the method of integrating factors for solving linear differential equations
  • Practice solving initial value problems with different exponential functions
  • Learn about the implications of initial conditions on the solutions of differential equations
  • Explore common mistakes in solving differential equations and how to avoid them
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Students studying differential equations, mathematics educators, and anyone looking to strengthen their problem-solving skills in calculus and differential equations.

mad_monkey_j
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Homework Statement


Find the solution to the initial value problem
dy/dx - y = e^3x
y(0) = 3

Homework Equations


e^∫p(x)

The Attempt at a Solution


Do I treat p(x) = -1?
I(x) = e^∫-1 = e^-x
e^-x(dy/dx) - ye^-x = e^3x . e^-x
e^-x(dy/dx) - e^-x . y = e^2x
e^-x . y = ∫e^2x
y = (2e^2x + c)/(e^-x)
y = C+2e^3x?
 
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mad_monkey_j said:

Homework Statement


Find the solution to the initial value problem
dy/dx - y = e^3x
y(0) = 3

Homework Equations


e^∫p(x)

The Attempt at a Solution


Do I treat p(x) = -1?
I(x) = e^∫-1 = e^-x
e^-x(dy/dx) - ye^-x = e^3x . e^-x
e^-x(dy/dx) - e^-x . y = e^2x
e^-x . y = ∫e^2x
y = (2e^2x + c)/(e^-x)
y = C+2e^3x?
Yes, in this case p(x)=-1. However, you're answer isn't correct as it doesn't satisfy the initial value problem. You have made a little slit in the second to last line of your working.
 

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