# Laplace transforms

Ok, this is the question:

Assume that the Laplace transform of x(t) is given as X(s)=s / (2s^(2) + 1).
Determine the Laplace transform of the following function.

g(t)=x(2t-5)u(2t-5)

How do I use the transform they have given me to solve this...I guess my major problem lies using time shifting and frequency scaling

Or if you have g(t)=t^2 sin(3t)x(t)......do you ignore x(t) since you usually ignore u(t) when it's at the end of the function?

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Galileo
Homework Helper
If you know the laplace transform of f(t), you how does the laplace transform of f(at) look? Or that of f(t-b)u(t-b)?

You can answer these questions generally, or you could setup the integral for the laplace transform of g(t) and make a change of variable.

Galileo said:
If you know the laplace transform of f(t), you how does the laplace transform of f(at) look? Or that of f(t-b)u(t-b)?

You can answer these questions generally, or you could setup the integral for the laplace transform of g(t) and make a change of variable.

What happens to u(2t-5) though? Do you actually take the Laplace transform of that?

Last edited:
GCT
Homework Helper
"u(2t-5)"

doesn't this refer to step functions

Galileo