Solving Laplace Transform: L{texp(9t)sin(2t)}

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SUMMARY

The discussion focuses on finding the Laplace transform of the function L{texp(9t)sin(2t)}. The key approach involves using the definition of the Laplace transform, specifically the integral form ∫₀^∞ f(t)e^{-st}dt, where f(t) = t e^{9t} sin(2t). Participants suggest applying integration by parts, with the initial choice of u = t and dv = e^{(9-s)t}sin(2t)dt, necessitating a second integration by parts to solve for v.

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Homework Statement



Find the Laplace transform of L{texp(9t)sin(2t)}

Homework Equations


(-1)^n F^n (s)


The Attempt at a Solution


I am not sure how to start it. The exp(9t) term throws me off. Usually I would just do (-1) F'(s) where F(s) is the laplace of sin(2t). But do I take the derivative of exp(9t) in addition to sin(2t)? Multiply them together?
Thanks in advance!
 
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You can start by using the definition of Laplace transform:
\int_0^\infty f(t)e^{-st}dt

Here, f(t)= t e^{9t} sin(2t) so that integral is
\int_0^t te^{(9- s)t} sin(2t) dt

Integration by parts should do that. The obvious choice is u= t, dv= e^{(9-s)t}sin(2t)dt and you will have to do another integration by parts to find v.
 

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