Fourier integral / transform ? What is it really?

In summary, to find phi(k), you can set t=0 and multiply both sides by e^{-i k' x} and integrate over x. This will yield a delta function in the integrand which allows you to evaluate the k integral. To simplify further, you can try completing the square in the exponential term by multiplying both sides by exp(-ik'x). This was suggested by Dr T.
  • #1
student1938
91
1
Find phi(k)

I need help with this question as far as what am I looking for and how do I use a Fourier transform cause I think I need one.

student
 

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  • #2
Any suggestions guys?
 
  • #3
Set t = 0, multiply both sides by
[tex]e^{-i k' x}[/tex]
and integrate over x. The integrand
[tex]e^{i(k-k')x}[/tex]
in the x integral will yield a delta function which let's you evaluate the k integral.
 
  • #5
If i multiple both sides by exp(-ik'x) the LHS gives exp(-ik'x-(x/2a)^2). I' m not sure what to do with this to simplify it further. Do i have to try to complete the square in this exponential now?
 
  • #6
student1938 said:
If i multiple both sides by exp(-ik'x) the LHS gives exp(-ik'x-(x/2a)^2). I' m not sure what to do with this to simplify it further. Do i have to try to complete the square in this exponential now?

Yes, that's what Dr T was suggesting.
 

What is a Fourier integral/transform?

A Fourier integral/transform is a mathematical tool used in signal processing and analysis to decompose a function into its constituent frequencies. It is named after French mathematician Joseph Fourier who first introduced the concept in the early 19th century. The transform can be thought of as a way to represent a function as a combination of sine and cosine waves, which allows us to analyze and manipulate signals in the frequency domain.

How is a Fourier integral/transform different from a Fourier series?

A Fourier series is used to represent a periodic function as a sum of sinusoidal functions, while a Fourier integral/transform is used to represent a non-periodic function as a combination of sinusoidal functions. In other words, a Fourier series is a special case of a Fourier integral/transform when the function being analyzed is periodic.

What is the purpose of using a Fourier integral/transform?

The main purpose of using a Fourier integral/transform is to simplify complex functions into simpler components in order to better understand and analyze them. This allows us to identify the frequencies present in a signal, filter out unwanted frequencies, and perform various operations such as convolution, differentiation, and integration on the original function.

What is the difference between a Fourier integral and a Fourier transform?

The terms "Fourier integral" and "Fourier transform" are often used interchangeably, but technically they refer to different things. A Fourier integral is the mathematical expression that represents the transform of a continuous function, while a Fourier transform is the actual result of applying the integral to the function. In other words, the Fourier transform is the output of the Fourier integral.

What are some real-world applications of Fourier integral/transform?

The Fourier integral/transform has a wide range of applications in various fields, including engineering, physics, mathematics, and computer science. Some common applications include digital signal processing, image and audio compression, solving partial differential equations, and analyzing physical phenomena such as heat transfer and fluid dynamics.

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