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: Help with volume

  1. Nov 28, 2011 #1
    1. The problem statement, all variables and given/known data

    Find the volume between the two surfaces

    z = 2x^2 + y^2

    z = 4 - y^2

    2. Relevant equations



    3. The attempt at a solution

    Ok so i found out that the surfaces intersect at a circle. When i solved i got

    x^2 + y^2 = 2, so the circle has a radius of sqrt 2.

    So these are the bounds i got. X goes from - sqrt 2 to sqrt 2, y goes from - sqrt 2-x^2 to sqrt 2-x^2 and z goes from 4-y^2 to 2x^2 + y^2.

    Is that right? If so, what is the equation I am integrating? Is it always integrating 1 dx dy dz?
     
  2. jcsd
  3. Nov 28, 2011 #2

    HallsofIvy

    User Avatar
    Science Advisor

    That would certainly work. And what would be the bounds on the z-integral?


    (Also, because of the circular symmetry, I would be inclined to use cylindrical coordinates- but you certainly can do it the way you suggest.)
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook




Loading...