Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Simple Fourier series problem

  1. Mar 17, 2010 #1
    1. The problem statement, all variables and given/known data
    Find the Fourier series for ex for x in (-1,1).
    Find the Parseval identity.

    2. Relevant equations

    3. The attempt at a solution
    [tex]c_{n}=\frac{1}{2}\int_{-1}^{1}e^{x}e^{-i n x}dx[/tex]
    Where cn are the coefficients of the Fourier series.

    I tried plotting
    [tex]\sum_{k=-\infty}^{\infty}c_{n}e^{i n x}[/tex]
    together with ex and it doesn't seem to be correct...

    Thank you for your help!
    Last edited: Mar 17, 2010
  2. jcsd
  3. Mar 17, 2010 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    For starters, your formula for cn is wrong. For period P = 2p:

    [tex]c_n = \frac 1 {2p}\int_{-p}^p f(x) e^{\frac {i n \pi}{p}}dx[/tex]

    In your problem p = 1.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook