Solving Diff EQ using a Laplace Transform

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Homework Statement


Solve the initial value problem:

\frac{dy}{dt} + 2y = u_2(t)e^{-t}

y(0) = 3

Where u_2(t) is a Heaviside Function with the discontinuity at t=2.

Homework Equations


The Laplace transform of a Heaviside function multiplied by another function:

L( u_a(t)f((t-a) ) = e^{-as}L(f(t-a)) Where L denotes the laplace tranform of a function.

The Attempt at a Solution



I know that in order to solve this equations using a laplace transform, I need to convert the RHS to the form of function in part 2. above. Once I do that I can take the Laplace Transform of both sides and then solve for L(y) and then y. I've been working at this for a while now, and I'm stuck on converting the RHS into a function whose transform I know. If I get this, then I can definitely do the rest of the problem. Any hints of converting this function into a workable form will be greatly appreciated.
 
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Figured it out! Thanks anyway!
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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