Solving Fourier Transform Problem: f(x) = e^(-pi*x^2)

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Discussion Overview

The discussion revolves around solving Fourier transform problems, specifically focusing on the function f(x) = e^(-pi*x^2) and its Fourier transform. Participants explore techniques for evaluating the integral involved in the Fourier transform, including completing the square and applying properties of Gaussian functions. A related problem involving f(x) = x * e^(-pi*x^2) is also introduced, prompting further inquiry into the application of previous results.

Discussion Character

  • Exploratory, Technical explanation, Homework-related, Mathematical reasoning

Main Points Raised

  • One participant requests assistance with integrating the Fourier transform of f(x) = e^(-pi*x^2).
  • Another participant suggests completing the square in the exponent as a first step.
  • It is noted that the Fourier transform of a Gaussian function results in another Gaussian function, and completing the square simplifies the integral.
  • A later post introduces a new function, f(x) = x * e^(-pi*x^2), and inquires whether results from the previous problem can be applied.
  • One participant mentions using the product rule for integration and suggests that the new function can be treated as a derivative of another function.

Areas of Agreement / Disagreement

Participants generally agree on the approach of completing the square for the initial problem, but the discussion remains unresolved regarding the application of previous results to the new function introduced.

Contextual Notes

Some assumptions about the properties of Fourier transforms and Gaussian functions are present, but not explicitly stated. The discussion does not resolve the mathematical steps for the new function.

Who May Find This Useful

Readers interested in Fourier transforms, Gaussian functions, and mathematical problem-solving techniques in physics and engineering may find this discussion relevant.

galipop
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Hi All,

I've been going through a few Fourier transform problems and I'm stuck with integrating this one:

f(x) = e^(-pi*x^2)

then

F(e^(-pi*x^2)) = integral (e^(-pi*x^2) * e^(-i*w*x)).dx

Can anyone help me out?

Many Thanks,

Pete
 
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1. You should first of all "complete the square" in the exponent.
2. If you've done that, and still got problems about how to evaluate the expression, try to explain what your problem is precisely.
 
The Fourier transform of a gaussian is a gaussian, complete the square and do the integral.
 
cheers... once I completed the square it was fairly straight forward.
 
I have another problem to solve, but it looks similar to the one above.

f(x) = x * e^(-pi*x^2).

So now there is an extra term.

Can I use the result from the previous problem to find the Fourier transform? Any hints to get me started would be greatly appreciated.

Cheers,

Pete
 
Note that you easily may replace f with some derivative, dG/dx.
Use the product rule for integration to compute the answer.
 

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