Laplace transform and fourier transform

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SUMMARY

The discussion centers on the relationship between the Fourier transform F{f(t)} and the Laplace transform L{f(t)}. It is established that F{f(t)} equals L{f(t)} when the Laplace variable s is substituted with jw, where j represents the imaginary unit. The definitions of both transforms are provided, highlighting the integral forms: F{f(t)} = ∫[f(t)e^-jwt]dt and L{f(t)} = ∫[f(t)e^-st]dt. The condition for this equality is that the imaginary axis must lie within the region of convergence for the Laplace transform.

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  • Understanding of Fourier transforms and their mathematical definitions
  • Knowledge of Laplace transforms and their integral forms
  • Familiarity with complex numbers, specifically the imaginary unit j
  • Concept of region of convergence in the context of Laplace transforms
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  • Study the properties of the Fourier transform and its applications in signal processing
  • Learn about the region of convergence for Laplace transforms and its implications
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Homework Statement


F{f(t)} is the Fourier transform of f(t) and L{f(t)} is the Laplace transform of f(t)

why F{f(t)} = L{f(t)} where s = jw in L{f(t)}


The Attempt at a Solution


I suppose the definition of F{f(t)} is

∫[f(t)e^-jwt]dt

where the lower integral limit is -∞ and higher intergral limit is +∞.

And I suppose the definition of L{f(t)} is

∫[f(t)e^-st]dt

where the lower integral limit is -∞ and higher integral limit is +∞.(that is bilateral Laplace transform)

and i think it is obviously to say F{f(t)} = L{f(t)} where s = jw in L{f(t)} just by substitute s = jw in ∫[f(t)e^-st]dt.

My solution is so simple that I can't believe it's a problem assigned by my professor!
Some guy please tell me if I am correct or not, and where it is.

Any reference or advise will be appreciated.

thanks in advance.
 
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Yes you are correct, as long as the imaginary axis is inside the region of convergence.
 
susskind_leon said:
Yes you are correct, as long as the imaginary axis is inside the region of convergence.

3x~ I am more confident~
 

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