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!

Double integral to find volume of a solid

  1. Dec 8, 2013 #1
    The problem statement, all variables and given/known data
    Set up a double integral to find the volume of the solid bounded by the graphs y=4-x2 and z=4-x2


    The attempt at a solution

    I drew myself a 3d graph but it's just a parabloid in the xy plane and a parabloid in the xz plane right? so I'm unsure how to set up my integral. This was my attempt, my thought was that perhaps z=4-x2 could be considered like the surface

    [itex]\int[/itex]20[itex]\int[/itex]4-x20 (4-x2) dy dx

    Could some one give me some input?
     
  2. jcsd
  3. Dec 8, 2013 #2

    LCKurtz

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    What you have done looks reasonable, but isn't there more detail about the region in question? Like first octant or y positive or something?? Otherwise the volume isn't bounded. Can't tell if your answer is correct without knowing more.
     
  4. Dec 8, 2013 #3
    oh yes sorry first octant is what it says. I wasn't entirely sure what that meant but I assumed it meant only the positive section of the 3d graph
     
  5. Dec 8, 2013 #4

    LCKurtz

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    The first octant is where all three variables are positive. If that's your region your integral is set up correctly.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted