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Graphing a circle

  1. Feb 1, 2009 #1
    Consider x^2 + y^2 – x + 2y + 1 = 0.
    (a) Find the coordinates of the center and the length of the radius.
    (b) Determine the coordinates of the intercepts.
    (c) Graph the circle.

    I'm really lost on this one. I tried plugging in numbers but I seriously doubt that's how I'm supposed to do it. Can someone point me in the right direction? Thanks
  2. jcsd
  3. Feb 1, 2009 #2


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    Standard Form versus General Form.
    Completing the Square.
  4. Feb 2, 2009 #3
    oh so just (x-1/2)^2 + (y+1)^2 = 1/4? center would be at (1/2, -1) and radius is sqrt(1/4)=(1/2)?
  5. Feb 2, 2009 #4


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    Yup! :biggrin:
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