Integrals of Fourier Series
- Subject: [mg3179] Integrals of Fourier Series
- From: goster at nature.Berkeley.EDU (George Oster)
- Date: 14 Feb 1996 03:57:48 -0600
- Approved: usenet@wri.com
- Distribution: local
- Newsgroups: wri.mathgroup
- Organization: Wolfram Research, Inc.
- Sender: daemon at wri.com
Suppose I want to substitue a Fourier Series into an integral: u[x_] := Sum[A[n] Sin[n Pi x/L], {n, 1, Infinity}] Integrate[(u''[x])^2, {x, 0, L}] This has an easy analytical solution that I can't get Mma to find, because Mma doesn't know that Sum and Integrate commute, and that Sin[n Pi] = 0 for all integer n. How to do this? GO _____________________________________________ Professor George Oster University of California 201 Wellman Hall Berkeley, CA 94720-3112 Phone & Fax: 510-642-5277 Email: goster at nature.berkeley.edu http://www.cnr.berkeley.edu/~goster/home.html