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!

Change of variables.

  1. Apr 29, 2004 #1
    Does anyone know of any sources that explain change of variables for double integrals. Actually, I get the change of variables thing, but a few of our problems don't give us the transforms. I don't understand how to create these myself.

    Here is an example:
    Math Problem

    So far, I found all the x,y coordinates of the joints because I know these joints or cross sections will exist after we change variables. However, I don't know where to go from there. Can I essentially make any transform I like?
     
  2. jcsd
  3. Apr 29, 2004 #2

    arildno

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    Dearly Missed

    1) Sources:
    In my opinion, an excellent intuitive understanding of the change of variables stuff can be found in Marsden&Tromba "Vector Calculus" (Lots of editions..).
    Instead of "burdening" the reader with rigorous proofs of the change-of-variables theorem, it has a clear focus on how to generate the "proper" area elements dA. (Lots of worked examples as well!)

    If you want a more rigorous treatment, one book is Marsden "Introduction to Real Analysis"

    2) Problem:
    Note that your region is bounded by two pairs of parallell lines.
    Try setting u=2x-y, v=3x+y, and see what you get.
     
  4. Apr 29, 2004 #3
    Wow, thank you. You just pointed out a valuable thing to me. I think I "get" what i'm supposed to do for these problems now. Thank you. :biggrin:
     
  5. Apr 29, 2004 #4
    Yes that is the way to go--- I just consider C o V as the "U-substitution" chapter but for Double Integrals. (Or even triple--- but i hate calculating 3x3 determinants!)
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Change of variables.
  1. Change of variable (Replies: 1)

  2. Change Of Variable (Replies: 11)

  3. Change of variable (Replies: 5)

  4. Change of variable (Replies: 7)

Loading...