Inverse Fourier Transform of 1/(1+8e^3jw): A Contour Integration Approach

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How do I find inverse Fourier transform of 1/(1+8e^3jw)??
Now, it would have been easier to find inverse of 1/(1+1/8e^jw), because that would be just (1/8)^n u[n]
i think i basically need a way to write 1/(1+8e^3jw) in a form described below:
A/(1+ae^(jw)) + B/(1+be^(jw) +C/(1+ce^(jw)
where a, b, c are less than 1.
How do I do that? partial fraction can be killing, because the process will be too long. Any other smarter methods?
 
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kolycholy said:
How do I find inverse Fourier transform of 1/(1+8e^3jw)??
Now, it would have been easier to find inverse of 1/(1+1/8e^jw), because that would be just (1/8)^n u[n]
i think i basically need a way to write 1/(1+8e^3jw) in a form described below:
A/(1+ae^(jw)) + B/(1+be^(jw) +C/(1+ce^(jw)
where a, b, c are less than 1.
How do I do that? partial fraction can be killing, because the process will be too long. Any other smarter methods?
find (2-e^(-jw))/(1+e^(-j3w)/8) inverse Fourier transform
 
kolycholy said:
How do I find inverse Fourier transform of 1/(1+8e^3jw)??
Now, it would have been easier to find inverse of 1/(1+1/8e^jw), because that would be just (1/8)^n u[n]
i think i basically need a way to write 1/(1+8e^3jw) in a form described below:
A/(1+ae^(jw)) + B/(1+be^(jw) +C/(1+ce^(jw)
where a, b, c are less than 1.
How do I do that? partial fraction can be killing, because the process will be too long. Any other smarter methods?

How about just muscle-through the contour integration:

\frac{1}{2\pi i}\int_{-\infty}^{\infty} \frac{e^{iwx}}{1+8e^{3iw}}dw

I suspect that may be just a sum of residues if x>0 however I've not gone over it rigorously so I'm not sure. Just another possibility you may wish to consider.
 
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Prove $$\int\limits_0^{\sqrt2/4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx = \frac{\pi^2}{8}.$$ Let $$I = \int\limits_0^{\sqrt 2 / 4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx. \tag{1}$$ The representation integral of ##\arcsin## is $$\arcsin u = \int\limits_{0}^{1} \frac{\mathrm dt}{\sqrt{1-t^2}}, \qquad 0 \leqslant u \leqslant 1.$$ Plugging identity above into ##(1)## with ##u...
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