Finding the Spectrum of a Function with Exponential and Trig Terms

frenzal_dude
Messages
76
Reaction score
0

Homework Statement


Hi, I need to find the spectrum of the following function:
i=I_0[e^{\frac{-0.01(cos(2\pi 1000t)+cos(2\pi 100000t))}{0.026}}-1]

Homework Equations


the Fourier Transform would be:
\int_{-\infty }^{\infty }I_0[e^{\frac{-0.01(cos(2\pi 1000t)+cos(2\pi 100000t))}{0.026}}-1]e^{-j2\pi ft}dt

The Attempt at a Solution


I'm not sure where to start because I'm not sure how to take the integral of an exponential when there is a trig term in there. Is this integral even possible or would it diverge to infinity?

Hope you guys can help,
frenzal
 
Physics news on Phys.org
I think I worked it out! I need to express the exp(x) function as a taylor series, and as n gets larger (greater than say 3) the number approaches 0! So you can approximate it up to n=3 and then integration should be ok.
 
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...
Back
Top