Fourrier Tranform and schwartz space

  • Thread starter Thread starter Stephen88
  • Start date Start date
  • Tags Tags
    Space
Click For Summary
The discussion focuses on the properties of functions in Schwartz space and their Fourier transforms. It establishes that if a function f belongs to Schwartz space, then the scaled function f_k(x) = f(kx) also belongs to Schwartz space. Additionally, it highlights the relationship between the Fourier transform of f and its scaled version, specifically that ^_f(e) = (1/k)^_f(e/k). The Fourier transform of the Gaussian function exp(−x^2/2) is given as sqrt(2pi)*exp(−e^2/2), and the discussion seeks to derive the Fourier transform for exp(−ax^2) using the earlier results. Participants are encouraged to provide guidance on the correctness of the approach and next steps.
Stephen88
Messages
60
Reaction score
0
^_f=fourrier transform of f.
f_k=f<sub>k
sqrt= square root

The function f belongs to the schwartz space and k>0 f_k(x)=f(kx).
1)show that f_k also belongs to the schwartz space and ^_f(e)=(1/k)^_f(e/k)
2)the fourrier transform of exp((−x^2)/2) is sqrt(2pi)*exp((−e^2)/2) use the first part to obtain the fourrier transform for exp(−ax^2)

Attempt:
f belongs to the schwartz space then f is infinitly diff also f(kx)=kf(x) which belongs to the schwartz space.
then f_k(x)=f(kx)=kf(x) which belongs to the schwartz space.
I don't know if this is correct or how to continue...any help will be great.Thank you
 
Physics news on Phys.org
Should I change something ?
 
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

Similar threads

  • · Replies 6 ·
Replies
6
Views
5K
  • · Replies 58 ·
2
Replies
58
Views
4K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 3 ·
Replies
3
Views
1K
  • · Replies 9 ·
Replies
9
Views
4K
  • · Replies 22 ·
Replies
22
Views
3K