Solving the Laplace Transform of an Irreducible Quadratic Factor

sunshine21
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Homework Statement



i need to find the laplace transform of this equation by using the partial fraction. it is an irreducible quadratic factor that i don't really know how to solve it.

Homework Equations



[(s+1)^2 + 6]/[(s+1)^2 +4]^2

The Attempt at a Solution


please help me, thanks. =)
 
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Actually, you want the inverse Laplace transform.

Instead of using partial fractions, I think it might be helpful to rewrite the numerator this way:
\frac{(s + 1)^2 + 6}{((s + 1)^2 + 4)^2} = \frac{(s + 1)^2 + 4 + 2}{((s + 1)^2 + 4)^2} = \frac{(s + 1)^2 + 4}{((s + 1)^2 + 4)^2} + \frac{2}{((s + 1)^2 + 4)^2}
 
ouh..when you make it simple, now i can see how to solve it.
i didnt realize it. maybe i think to much on how to cancel out the square at the denominator.
thanks Mark44. your information is very helpful. thank you so much =))
 
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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