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: Spherical coordinates path integral and stokes theorem

  1. Sep 13, 2015 #1
    1. The problem statement, all variables and given/known data
    image2 (1).JPG

    2. Relevant equations

    The path integral equation, Stokes Theorem, the curl

    3. The attempt at a solution

    image1 (1).JPG

    sorry to put it in like this but it seemed easier than typing it all out. I have a couple of questions regarding this problem that I hope can be answered. First, does this look like the right path to the solution? I feel like I should be involving the Jacobian in the integral somewhere. Second, would the surface element be r2sin(θ) dθdφ for this and problem 2? Any help is greatly appreciated!
  2. jcsd
  3. Sep 14, 2015 #2


    User Avatar
    Homework Helper
    Gold Member
    2017 Award

    Looks to me like you are approaching problem 1 correctly. I'm not sure why you feel that a Jacobian [determinant (?)] should be involved here. Your surface area element is correct for problem 1. For Stokes' theorem you will need to consider the direction of the area vector for the surface element.

    For the second problem, you do not have the correct surface area element. As you move around on the cone, there is no change in ##\theta##. So, ##d\theta = 0## and your expression for the surface element would be zero.

    Consider how you would express the area of an infinitesimal patch of the cone in the shape of a rectangle (sort of), where two of the sides are due to an infinitesimal change in ##r## and the other two sides are due to infinitesimal changes in ##\phi##. You should also consider how you would express the area vector for this patch.
    Last edited: Sep 14, 2015
  4. Sep 14, 2015 #3
    Thanks for the help! The more I thought about it the more I understood why the Jacobian shouldn't be involved. I'll checkout that area vector and the direction of it.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted