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Homework Help: Changing rectangular coordinates to polar coordinates ?

  1. Jun 6, 2009 #1
    1. The problem statement, all variables and given/known data

    Hey i know that we can change it by using

    but finding some problems in converting the area surrounded by
    X=0; Y=0; x+y=1; x+y=2 to polar coordinates .

    yr of course you can convert X=0 to theta=pi/2 and Y=0 to theta=0;

    But i don't how to convert other 2 boundaries to polar coordinates.Can anyone help me
  2. jcsd
  3. Jun 6, 2009 #2


    User Avatar
    Homework Helper

    Polar coordinates are given by [itex]x=r \cos \theta, y=r \sin \theta, r=x^2+y^2[/itex].
  4. Jun 6, 2009 #3


    Staff: Mentor

    You can convert rectangular coordinates to polar form, and vice versa. Here is a summary of the conversion formulas going both ways.

    Convert rectangular to polar

    r = \pm \sqrt{x^2 + y^2}[/tex]
    [tex]\theta = tan^{-1} (y/x)[/tex]

    Convert polar to rectangular
    [tex]x = r cos(\theta)[/tex]
    [tex]y = r sin(\theta)[/tex]
  5. Jun 6, 2009 #4
    yr of course i know those two equations !!!!!and i have been successful in converting two boundaries of the region .But my problem is how to convert X+Y=1 and X+Y=2 to polar coordinates.
    I hope u guys got my question !!!!!!!
  6. Jun 6, 2009 #5


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    Science Advisor
    Homework Helper

    Then use those equations. Substitute them into x+y=1 and x+y=2 and solve for r to get the upper and lower bounds for the r integration in terms of theta.
  7. Jun 6, 2009 #6
    ah ok i got it now thanks !!!!!!!
  8. Jun 6, 2009 #7


    Staff: Mentor

    If you look carefully, you'll see that there are four equations.
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