Author Topic: excersice 1, chap 7.3  (Read 915 times)

Jingxuan Zhang

  • Elder Member
  • *****
  • Posts: 106
  • Karma: 20
    • View Profile
excersice 1, chap 7.3
« on: March 17, 2018, 05:34:56 PM »
http://www.math.toronto.edu/courses/apm346h1/20181/PDE-textbook/Chapter7/S7.3.html#sect-7.3.1

Exercise 1 appears quite strange. if $f=0$ on $\Omega=\{\|x\|\geq R\}$ and $u(y)=\int_\Omega G(x,y)f(x)\,dx$, then shouldn't this integral vanish instead of giving that curious form?

Victor Ivrii

  • Administrator
  • Elder Member
  • *****
  • Posts: 2553
  • Karma: 0
    • View Profile
    • Personal website of Victor Ivrii
Re: excersice 1, chap 7.3
« Reply #1 on: March 17, 2018, 05:56:10 PM »
The formula you refer to is good only for $\Omega=\mathbb{R}^n$. In all other cases it contains integrals over boundary, which are not $0$