Total power contained in 10.0[cos(160.7*pi*t)]^4 (Fourier Series)

1. Mar 31, 2013

Jd303

1. The problem statement, all variables and given/known data

Compute the power contained in the periodic signal x(t) = 10.0[cos(160.7*pi*t)]^4

2. Relevant equations

3. The attempt at a solution

Hey guys,
I have just started Fourier Series and am struggling with this one. Without writing all my calculations, -I start with inverse Euler formula.
-Then integrate x(t)*e^(-j*ω*k*t) with respect to t. From 0 to (To)
-Then consider the value of the final exponentials when k is an odd and even number.

However i calculate that the answer for ak for any value of k to be 15/4?

Once again I have only started Fourier recently so any direction would be much appreciated.

Last edited by a moderator: Mar 31, 2013
2. Mar 31, 2013

vela

Staff Emeritus

Another approach you might try is using trig identities to find the Fourier series.

3. Apr 1, 2013

Jd303

Provided are my calculations in the attachment
-The function has already been converted using the inverse Euler formula
- σ is equal to 160.7*pi*t
- The fundamental frequency is 2*σ/(2*π)

-Anyway to calculate this equation is fine, inverse euler was just given as a suggestion to begin.

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