Feedback for Hw Due 03 25 2015

Feedback for Hw Due 03 25 2015

Show your work. The integral of t*e^(-st) is not immediate. The limit of t*e^{-(s-ia)*t}, as t goes to +infinity, is not immediate either.
They require work (integration by parts; L’Hospital’s rule respectively). Show your work. The answers are in the back of the book.

Problem 5.1/8. Many combinations of M,a,k work. There is no unique solution.
If you do not know what to do, pick the values of k,a randomly, graph |f(t)| and k*e^(at), and find some M after which the function
k*e^(at) becomes larger than |f(t)|. If you are unable to find such an M, increase the values of k,a, until you succeed.

In section 5.2, there are formulas for the Laplace transform of t,t^2, t*sin(at),t*cos(at). In section 5.1, you have to find the Laplace transform integrating “by hand”, not using the formulas.
In the exam, you can use the formulas, unless the problem explicitly says not to do so.


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