# Fourier transform

kolycholy
how can I find Fourier transform of 1/(1+4t^2)?
hmmm =/

moe_3_moe
try to take x=2t and use the symmetry or duality property and then the scaling property

antoker
Use the fact that your expression can be expressed as $$\int{\frac{f(t)}{g(t)}dx}$$, where $$f(t) = e^{-j\omega t}, g(t)=1+4t^{2}$$ and proceed as stated by the rule. If i remember it correctly it goes something like $$\frac{f'(t)g(t)-g'(t)f(t)}{g(t)^{2}}$$

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Manchot
Use the fact that your expression can be expressed as $$\int{\frac{f(t)}{g(t)}dx}$$, where $$f(t) = e^{-j\omega t}, g(t)=1+4t^{2}$$ and proceed as stated by the rule. If i remember it correctly it goes something like $$\frac{f'(t)g(t)-g'(t)f(t)}{g(t)^{2}}$$
You've mixed up differentiation and integration...

moe_3_moe
manchot is right ... so complicated ... i think the properties of the Fourier transformation is better

antoker
damn... you're right ;)

kolycholy
i tried taking a look at the Fourier transform properties..
but hmm, still confused

moe_3_moe
check the scaling and the symmetry property ... sorry i can't tell the answer ... it is the rules ...