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!

Equation of a circle / polar coordinates

  1. Dec 4, 2011 #1
    I was looking at the equation of a circle in polar coordinates on wikipedia,

    http://en.wikipedia.org/wiki/Polar_coordinate_system

    and I understand that a is the radius of the circle, and that (r0, phi) is the center of the circle. But I don't see what the r and theta refer to :(.
     
  2. jcsd
  3. Dec 4, 2011 #2

    eumyang

    User Avatar
    Homework Helper

    r and θ are just the variables in the equation.

    Just like in rectangular coordinates, given a center (h, k) and radius r,
    (x - h)2 + (y - k)2 = r2
    is the equation of the circle, and x and y are the variables.

    Or am I misunderstanding your question? :confused:
     
  4. Dec 4, 2011 #3
    So do they just represent a point inside the circle?
     
  5. Dec 4, 2011 #4

    eumyang

    User Avatar
    Homework Helper

    No, they represent a set of points that lie on the circle, not inside.
     
  6. Dec 4, 2011 #5
    What do you mean by [[/B]on[/B]? And by the way; sorry for giving you a hard time. English is not my first language.
     
  7. Dec 4, 2011 #6

    eumyang

    User Avatar
    Homework Helper

    See attached picture. The red point is on the circle, while the blue point is inside the circle.
     

    Attached Files:

Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Equation of a circle / polar coordinates
  1. Polar coordinate (Replies: 9)

  2. Polar Coordinates (Replies: 2)

  3. Polar coordinates (Replies: 20)

Loading...