1. Not finding help here? Sign up for a free 30min 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!

How to find the domain in one dimension

  1. Jan 21, 2010 #1
    1. The problem statement, all variables and given/known data
    I am trying to find the domain of the following..

    R^2 to R^3 of g(x,y) = (x-y,x+y,3*x)
    R^3 to R of h(x,y,z) = x/(y+z)

    2. Relevant equations



    3. The attempt at a solution

    I don't know how to start. I know how to find the domain in one dimension but how do you do it in 2 or 3 dimensions???
    Thanks
     
    Last edited: Jan 21, 2010
  2. jcsd
  3. Jan 21, 2010 #2

    Dick

    User Avatar
    Science Advisor
    Homework Helper

    Re: Domain

    Your second function is actually R^3->R. Since they didn't tell you what the domain is, you just want to pick the domain of f:A->B to be all of the points in A where the function is defined.
     
  4. Jan 21, 2010 #3
    Re: Domain

    so for the first one can just do from (-infinity to infinity) ????

    can i just put in any value of x i want to?
     
  5. Jan 21, 2010 #4

    Mark44

    Staff: Mentor

    Re: Domain

    For the first one, your domain is not just R, the real line; it's the real plane, R2. For the second one, there is a restriction on y and z.
     
  6. Jan 21, 2010 #5

    Dick

    User Avatar
    Science Advisor
    Homework Helper

    Re: Domain

    Basically, yes. But the domain isn't (-infinity,infinity), that's a subset of R. The domain should be a subset of R^2. How about saying it's ALL of R^2?
     
  7. Jan 21, 2010 #6
    Re: Domain

    So the first one domain = R^2 the real plane

    second one = is y+z not equal to '0'

    is that right?
     
  8. Jan 21, 2010 #7

    Mark44

    Staff: Mentor

    Re: Domain

    Yes, pretty much. You can say it a little nicer as
    [tex]\{(x, y, z)\in R^3 | y + z \neq 0\}[/tex].
     
  9. Jan 21, 2010 #8
    Re: Domain

    that looks nice thanks
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: How to find the domain in one dimension
  1. Finding the domain. (Replies: 3)

  2. Finding domain (Replies: 3)

Loading...