How to Solve Non-Homogeneous Laplace Equations with Right-Hand Side Terms

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In summary, the conversation discusses the process of solving a differential equation with a right-hand side (RHS) that is not homogeneous. The speaker initially gets stuck in the process but then realizes that they need to use partial fractions. They reach a final solution of Y(s)= 4/(s-1), which can then be used to determine the value of y(t).
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reece
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Hi, I can solve homogeneous laplace fine, but with RHS i get stuck half way through.

Q:
y' +3y = 8e[tex]^{t}[/tex]
y(0) = 2

Working as if it was homogeneous..

sY(s) - 2 + 3Y(s) = 8 . [tex]\frac{1}{s-1}[/tex]
Y(s) (s+3) - 2 = 8 . [tex]\frac{1}{s-1}[/tex]

I think the next step is
Y(s) = [tex]\frac{2}{s+3}[/tex] + [tex]\frac{8}{s-1}[/tex]

and then do partial fractions but i don't think it leads me to where I need to be. I think i need to make it into a heaviside ??

Any help would be great. thanks
 
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  • #2
After the second step you should get Y(s)= 8/((s-1)*(s+3)) + 2/(s+3)

After doing a partial fraction expansion you get Y(s)= 4/(s-1)

which should give you y(t)= ? (I think you can figure it out from here.)
 

FAQ: How to Solve Non-Homogeneous Laplace Equations with Right-Hand Side Terms

What is a non-homogeneous Laplace equation?

A non-homogeneous Laplace equation is a partial differential equation that involves second-order derivatives with respect to multiple independent variables, and also includes a non-zero source term. It is often used to model physical systems where there is an external force or input affecting the behavior of the system.

How is a non-homogeneous Laplace equation solved?

A non-homogeneous Laplace equation is typically solved using separation of variables, where the solution is expressed as a product of functions of each independent variable. Boundary conditions are then applied to determine the coefficients of each term in the solution. Alternatively, numerical methods such as finite difference or finite element methods can also be used to solve the equation.

What is the difference between a non-homogeneous Laplace equation and a homogeneous one?

A homogeneous Laplace equation does not have a non-zero source term, meaning that the equation only includes second-order derivatives of the dependent variable. This results in a simpler solution compared to a non-homogeneous equation. In contrast, a non-homogeneous equation includes a source term, making the solution more complex.

What are some real-world applications of non-homogeneous Laplace equations?

Non-homogeneous Laplace equations have many applications in physics, engineering, and other fields. They can be used to model heat transfer, fluid flow, electrostatics, and other physical phenomena. They are also commonly used in image and signal processing, where they are used to enhance or filter images and signals.

What are some techniques used to solve non-homogeneous Laplace equations?

As mentioned earlier, separation of variables and numerical methods are commonly used to solve non-homogeneous Laplace equations. Additionally, integral transforms such as the Fourier and Laplace transforms can also be used to solve these equations. In some cases, Green's functions and the method of eigenfunction expansions can also be employed to find solutions to non-homogeneous Laplace equations.

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