Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Solving Laplace Eqn by Separation of vbls

  1. Mar 14, 2010 #1
    Okay, I'm stumped at what seems like a very simple mathematical step

    I start with

    Then, the next step is

    I see what changed, but I don't understand exactly what happened. Can someone please explain? Thanks in advance!
  2. jcsd
  3. Mar 14, 2010 #2


    User Avatar
    Science Advisor
    Gold Member

    They just applied the product rule:

    [tex] \frac{\partial}{\partial x} \left(f(x)g(x)\right) = g(x) \frac{\partial f(x)}{\partial x} + f(x) \frac{\partial g(x)}{\partial x} [/tex]
  4. Mar 14, 2010 #3

    Thanks. Also, just realized this is in the wrong forum. I'm on a roll...
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook