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: Function of 3 variable help!

  1. Oct 14, 2013 #1
    1. The problem statement, all variables and given/known data

    The problem is given in the picture attached. However we are given the equation of a 4 dimensional shape with certain choice given to explain the shape in that dimension.

    2. Relevant equations

    Equations of different shape such as:

    sphere: √(x^2+y^2+z^2) = r
    Ellipse: (x-h)/a^2 + (y-k)/b^2 = K
    Hyperbola: (x-h)/a^2 - (y-k)/b^2 = 1

    3. The attempt at a solution

    Well for question one and two, I said 1 ( which is w=x^2+y^2+z^2) is a "a collection of equally spaced concentric spheres" and 2 ( w=√(x^2+y^2+z^2) was "a collection of unequally spaced concentric spheres ".Though I know the difference between both is the radius where one is w and the other is √w. But why does have a radius of √w make the sphere unequally spaced?

    My teacher barely touched the topic so I have a hard time figuring out how to visualize these shapes.
  2. jcsd
  3. Oct 14, 2013 #2
    I couldn't see my attachment... here it is ( trying again)

    Attached Files:

  4. Oct 15, 2013 #3
    You are correct about #1.
  5. Oct 15, 2013 #4
    You are correct about #1. I do know the answers to some of the others, and can guess some, but perhaps it would be best to tell you how I would go about this if I had to do the problem.

    Go back to 3 dimensions, and look up the equations of the conic sections. Answer the questions when z is omitted. It has to be similar in 4 dimensions.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted