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: Surface Integral

  1. Feb 24, 2010 #1

    bon

    User Avatar

    1. The problem statement, all variables and given/known data

    So trying to find the Integral of A.n dS where A is (y,2x,-z) and S is the surface of the plane 2x+y = 6 in the first octant cut off by the plane z=4

    2. Relevant equations



    3. The attempt at a solution

    So i always solve these by projection...but im a bit confused this time..

    normally the surface is in the form z=f(x,y) so i do z-f(x,y) and take grad to find the normal..

    so is the normal vector here just (2,1)? ie. grad 2x-y-6 = 0?

    In which case is the integral just the double integral of (y,2x,-4).(2,1,0) dA?

    Im a bit confused..Any help would be great!
     
  2. jcsd
  3. Feb 25, 2010 #2

    bon

    User Avatar

    Any ideas..?
    I'm pretty confused about which plane you project onto to solve this...

    Thanks!
     
  4. Feb 25, 2010 #3

    bon

    User Avatar

    So do you project onto y-z plane?

    and is the integral therefore the 1/2 times the double integral of A.(2,1,0) dydz?
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook