(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Please take a look at the example at the bottom (at eq. 18:18, at page 619):

http://books.google.dk/books?id=9p6...g=iAUGf-f9d5uHRwwYZnpFpA8HJDA&hl=da#PPA619,M1

Q1: In case (ii), why do they add g(x^2+y^2)?

Q2: Why do they not add it in case (i)?

Q3: In case (ii), if I chose f(p) = p + 1 instead of f(p) = 2p, then the solution would be u(x,y) = 1+ x^2 +y^2 + g(x^2 + y^2), right?

I hope you can help me; I find this really hard to understand, and I've spent hours trying to find out, but I find that the book is poorly written. They don't emphasize the important things at all, and the reader is left behind with so many questions.

Thanks in advance.

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Linear partial differnetial equations (PDE's)

**Physics Forums | Science Articles, Homework Help, Discussion**