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Laplace partial fractions

nobodythere · 2007-11-17 17:56:29

Hi, trying to solve this problem: Inverse laplace of: 2s+5--------------s^2 + 6s + 9 I got the denominator to (s+3)(s+3), then thought I'd try split them up into partial fractions but it seems that because the two quadratic solutions are the same that partial fractions doesn't really work. Any help please?

17-11-2007 5:56pm

#1
nobodythere

Closed Accounts Posts: 2,349 ✭✭✭

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Hi, trying to solve this problem:
Inverse laplace of: 2s+5 -------------- s^2 + 6s + 9

I got the denominator to (s+3)(s+3), then thought I'd try split them up into partial fractions but it seems that because the two quadratic solutions are the same that partial fractions doesn't really work. Any help please?

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Comments

#2 17-11-2007 6:56pm

Michael Collins

Moderators, Science, Health & Environment Moderators Posts: 1,852 Mod ✭✭✭✭

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Posts: 1736

Yeah, your guess is correct. You need to find the residues a different way when one of the roots is repeated. Think differentiation...I'm heading out now so that's the best I can do. Have a go at that anyway...

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