Initial value ODE with shifting forcing function

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Discussion Overview

The discussion revolves around solving an initial value ordinary differential equation (ODE) using the Laplace Transform method. Participants are exploring the transformation of a shifting forcing function and seeking clarification on the application of the Laplace Transform, particularly regarding the Heaviside step function.

Discussion Character

  • Technical explanation
  • Mathematical reasoning

Main Points Raised

  • One participant presents an equation derived from applying the Laplace Transform to the ODE and seeks assistance with the inverse transformation of a specific term.
  • Another participant clarifies that the standard symbol for the step function is u(t) and suggests consulting Laplace transform tables.
  • A participant requests further clarification on the Laplace Transform of the function e^(at)*u(t).
  • Another participant proposes using the shifting property of the Laplace Transform to derive the transform of the Heaviside step function, providing a specific example related to the shifting.

Areas of Agreement / Disagreement

Participants generally agree on the use of the Laplace Transform and its properties, but there are varying levels of understanding and specific questions that remain unresolved.

Contextual Notes

Some assumptions about the definitions of the functions and properties of the Laplace Transform are not explicitly stated, and there may be unresolved mathematical steps in the transformation process.

Who May Find This Useful

This discussion may be useful for students and practitioners dealing with differential equations, particularly those interested in the application of Laplace Transforms in solving initial value problems.

Houeto
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Use laplace Transform to solve this ode:
upload_2016-7-21_21-49-59.png


So I got:

sV(s)-V(0)-12V(s)=U(s+5)
V(s)(s-12)=U(s+5)+1
V(s)=[U(s+5)+1]/(s-12)

Now to go back to time domain with Inverse Laplace Transform...My question is, how to transform U(s+5)/(s-12)?

Any help?

Thanks guys
 
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I think it may help you to know that u(t) is the standard symbol for the step function, which has a known Laplace transform. Check your tables.
 
Thanks
 
@Twigg , can you shed some lights on Laplace Transform of e^(at)*u(t)?

Thanks
 
I'm pretty sure you just apply the shifting property to the Laplace transform of the Heaviside step function. The Laplace transform of ##u(t)## is ##\frac{1}{s}##, so the Laplace transform of ##e^{-5t} u(t)## is ##\frac{1}{s + 5}##. Just like you did in your first post.
 
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Thanks
 

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