- #1
Jalo
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Homework Statement
a) Find the Fourier transform of the function f(x) defined as:
f(x) = 1-3|x| , |x|<2 and 0 for |x|>2
b) Find the values of the inverse Fourier transform of the function F(k) obtained in a)
Homework Equations
F(k) = [itex]\frac{1}{\sqrt{2π}}[/itex][itex]\int[/itex] f(t) eikx dx
f(x) = [itex]\frac{1}{\sqrt{2π}}[/itex][itex]\int[/itex] F(k) e-ikx dk
(Both integrals are from -inf to +inf)
The Attempt at a Solution
I solved the a) and got the result:
F(k) = [itex]\frac{1}{\sqrt{2π}}[/itex](-[itex]\frac{10}{k}[/itex]sin(2k) - [itex]\frac{6}{k^2}[/itex]cos(2k) + [itex]\frac{6}{k^2}[/itex])
The problem arrises at question b)
If I insert the function F(k) into the formula
f(x) = [itex]\frac{1}{\sqrt{2π}}[/itex][itex]\int[/itex] F(k) e-ikx dk
I'll get an integral that I can't solve.. I tried inserting the definition of F(k) into the formula above, and I got:
f(x) = [itex]\frac{1}{2π}[/itex][itex]\int[/itex] dk e-ikx [itex]\int[/itex] dx f(x) eikx
I get stuck here tho... I suspect it has something to do with delta dirac's function, but it is not making much sense in my head right now...
If someone could point me in the right direction I'd appreciate!
Thanks.