# Homework Help: New to the forums need some help with signal analysis

1. Oct 2, 2011

### stefan1988

Im taking This class EEL3135 and im very lost and confused as to how to study or where to find resources to understand the material.

does anybody know of a good website for beginner signal analysis? or a good reference ebook etc to help me out with it? the ones i seen are far too advanced and complicated for the stuff we doing.

1. The problem statement, all variables and given/known data
here is the problem im looking at.
a.Determine a formula for x(t) as the real part of a sum of complex exponentials.
b.what is the fundamental period for x(t)
c.plot the spectrum for x(t)
X(T)=sin^3(27PI t)

2. Relevant equations
euler inverse cosθ=(e^θ+e^θ)/(2) i dont really understand why we use this formula

3. The attempt at a solution

i started for first expansion i got
(-e^54pit)/4 +0.5+(e^-54pit)/4

after third expansion i got
(-e^81pit)/(8j)+(3e^27pit/8j)+(-3e^27pit)/(8j)+ (-e^81pit/8j)

is there an easier way to do this than big expansion?

2. Oct 3, 2011

### issacnewton

Last edited by a moderator: Apr 26, 2017
3. Oct 30, 2011