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Homework Help: Stokes' Theorem ( Surface Integral )

  1. Jan 20, 2009 #1


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    [SOLVED] Stokes' Theorem ( Surface Integral )

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

    Use stokes' theorem to find the value of the surface integral [tex]\int\int[/tex] (curl f) dot n) dS over the surface S:

    Let S by the part of the plane z=y+1 above the disk x^2+y^2<=1, and let f=(2z,-x,x).

    2. Relevant equations

    http://img187.imageshack.us/img187/291/1fdf437d8e18a23191b63dfnj8.png [Broken]

    3. The attempt at a solution

    So, S has a minimum at (0,-1,0) and a maximum at (0,1,2). This gives me a right triangle, with one of its legs from (0,-1,0) to (0,1,0), and the other from (0,1,0) to (0,1,2). Its hypotenuse is 2sqrt(2) units long, meaning the slanted elliptical surface has a long axis length of 2sqrt(2) and a short axis length of 2 (from (-1,0,1) to (1,0,1)).

    Now, should I somehow try to calculate the circulation around this region using stokes's theorem (maybe have a z component of the path being some sort of trigonometric function?), or is there a better way to do this (by still using Stokes' theorem, though)?

    EDIT: Nevermind. The best way is to just use x = cos(theta) , y = sin(theta), z = sin(theta)+1 after applying stoke's theorem.
    Last edited by a moderator: May 3, 2017
  2. jcsd
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