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 Area problem

  1. Jan 31, 2007 #1
    1. The problem statement, all variables and given/known data
    I am wondering if someone could help me with the following? I am supposed to find the area of the finite part of the paraboloid y = x^2+z^2 that's cut off by the plane y = 25. Now, wouldn't this be the same as the paraboloid z = x^2+y^2 that's cut off by the plane z = 25?

    So, if that's right, then the surface area is ∫∫√((dz/dx)^2+(dz/dy)^2+1).
    This seems easier to do in polar coordinates, so we basically have the following:

    ∫∫(1+4r^2)? And, r would be from 0 to 5, and 0≤θ≤2*pi?

    Am I doing something wrong here? Or, how do I "project" the surface unto the x-z plane? Thanks!!!
  2. jcsd
  3. Jan 31, 2007 #2


    User Avatar
    Science Advisor
    Homework Helper

    Why do you think you are doing something wrong? Well done.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook