Toronto Math Forum
APM3462018S => APM346Lectures => Topic started by: Jingxuan Zhang on March 17, 2018, 05:34:56 PM

http://www.math.toronto.edu/courses/apm346h1/20181/PDEtextbook/Chapter7/S7.3.html#sect7.3.1
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?

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 $0$