Laplace Transform IVP (Easy I think)

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SUMMARY

The discussion focuses on solving the initial value problem (IVP) using Laplace transforms for the differential equation y'' + 4y = 0 with initial conditions y(0) = 5 and y'(0) = 0. The user correctly applies the Laplace transform, leading to the equation Y(s)(s² + 4) = 5s + 20. The solution for Y(s) is derived as Y(s) = 5/s, indicating that the inverse Laplace transform yields the solution y(t) = 5. The user identifies a mistake in their initial interpretation of the equation, clarifying that the term is not 4y'.

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Homework Statement


Use Laplace transforms to solve the initial value problems.
##y''+4y=0;## ##y(0)=5;## ##y'(0)=0##

Homework Equations





The Attempt at a Solution


$$y''+4y=0$$ $$L(y'')+L(4y)=L(0)\implies s^{2}Y(s)-sy(0)-y'(0)+4(sY(s)-y(0))=0\implies s^{2}Y(s)+4sY(s)-5s-20=0$$ $$Y(s)(s^{2}+4s)=5s+20\implies Y(s)=\frac{5}{s}$$
Now I'm supposed to take the inverse laplace of that which would just be 5. I'm not sure what to do with this now.
 
Last edited:
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Found my mistake, it's not 4y'...
 

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