Results 1 to 4 of 4

Math Help - Two integrals I encountered in fourier analys

  1. #1
    Member
    Joined
    Nov 2009
    Posts
    177

    Two integrals I encountered in fourier analysis

    (1)

    u(t)=\left\{\begin{array}{ccc}2,&0\leq t < 1\\1, & 1  \leq t < 2\\0, & 2 \leq t < 3\end{array}\right.

    \frac{1}{3}\int_{0}^{3}u(t)e^{-in\frac{2\pi}{3}t}dt, n = 0,1,2,...




    (2)

    \frac{1}{\pi}\int_0^{\pi} |\cos t|e^{-i2nt}dt

    I know some rules about odd and even functions but I can't seem to apply them here.
    Last edited by Mondreus; August 31st 2010 at 12:50 PM.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    A Plied Mathematician
    Joined
    Jun 2010
    From
    CT, USA
    Posts
    6,318
    Thanks
    4
    Awards
    2
    For both of those integrals, you'll need to break up the region of integration so that you can write a more explicit formula for u(t).
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Member
    Joined
    Nov 2009
    Posts
    177
    I can solve the integrals, but the answer I'm getting is too complex (no pun intended heh). The answer is supposed to be fourier coefficients that I need to generalize for different values of n, and I don't see how I can get my answer to be what the textbook says.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    A Plied Mathematician
    Joined
    Jun 2010
    From
    CT, USA
    Posts
    6,318
    Thanks
    4
    Awards
    2
    Ok: what answer are you getting? And what is the book's answer?
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Solution to a PDE in terms of Fourier Integrals
    Posted in the Differential Equations Forum
    Replies: 0
    Last Post: April 23rd 2011, 10:00 AM
  2. interesting problem encountered
    Posted in the Algebra Forum
    Replies: 2
    Last Post: January 10th 2011, 12:32 PM
  3. Fourier Integrals?
    Posted in the Differential Geometry Forum
    Replies: 7
    Last Post: April 19th 2010, 08:43 PM
  4. A few problems encountered in exam revision
    Posted in the Calculus Forum
    Replies: 2
    Last Post: January 19th 2010, 01:12 PM
  5. Fourier Series integrals help
    Posted in the Calculus Forum
    Replies: 1
    Last Post: February 9th 2009, 12:01 PM

Search Tags


/mathhelpforum @mathhelpforum