1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
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: Functions with multiple variables

  1. Sep 29, 2007 #1
    1. The problem statement, all variables and given/known data

    I have a function f(x,y,z) = 1/(x^2+y^2+z^2). I have to find the domain.
    It is R^3, but x^2+y^2+z^2 != 0. How do I write that and am I correct?
  2. jcsd
  3. Sep 29, 2007 #2
    you're right. Think where are the points with x^2+y^2+z^2=0.
    You can write the domain as: [tex]\mathbb{R}^3 \setminus{\{0,0,0\}}[/tex]
  4. Sep 29, 2007 #3


    User Avatar
    Science Advisor

    [tex]\{ (x,y,z)| x^2+ y^2+ z^2\ne 0 \}[/tex]
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook