Inverse Fourier transforms and partial fractions

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SUMMARY

The discussion centers on finding the inverse Fourier transform of the function 1/(iw+3)³. Participants express challenges in applying partial fraction decomposition due to the cubic term and explore the differentiation property, which complicates the transformation. The consensus is that while partial fractions can simplify some inverse transforms, they are not effective for this cubic case. The final expression derived is 1/(iw+3) = 3/(w² + 9) - iw/(w² + 9) = (1/√(w² + 9))e^(i arctan(w/3)).

PREREQUISITES
  • Understanding of Fourier transforms and their properties.
  • Familiarity with partial fraction decomposition techniques.
  • Knowledge of complex analysis, particularly dealing with cubic functions.
  • Basic integration skills, especially in the context of inverse transforms.
NEXT STEPS
  • Study the differentiation property of Fourier transforms in detail.
  • Learn advanced techniques for handling cubic terms in Fourier transforms.
  • Explore the relationship between Fourier and Laplace transforms.
  • Practice problems involving inverse Fourier transforms with various function types.
USEFUL FOR

Students preparing for exams in signal processing, mathematicians focusing on Fourier analysis, and anyone seeking to deepen their understanding of inverse Fourier transforms and partial fraction techniques.

Luongo
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1. find the inverse FT of 1/(iw+3)3



2. well partial fractions gave the same thing back... I'm not sure how to transform this as there's no property that deals with cubics.



3. i tried using the differentiation property but it doesn't work as it increases the power of 3 to 4 and so on... how would i go about computing the inverse Fourier transform of this? is there a property involving powers out there? how would you
 
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I'm not familiar with using partial fractions for inverse Fourier transforms but it looks like that would be easy to integrate directly. Do you mean Laplace transform?
 
HallsofIvy said:
I'm not familiar with using partial fractions for inverse Fourier transforms but it looks like that would be easy to integrate directly. Do you mean Laplace transform?
the course is called "the Fourier transform and its applications" so yeah I'm pretty sure i don't mean laplace transform. can someone help please my midterms tommorow and i have no clue..
 
Hey Luongo, did you ever figure out how to do this problem? I have the exact same question on my problem set and have no idea what to do either, I ended up trying partial fractions just like you and it didn't work so I'm stumped.
 
1/(iw+3) = 3/(w2 +9) - iw/(w2 +9) = (1/√(w2 +9))ei arctan(w/3)
 

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