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Math Help - Cartesian Formula

  1. #1
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    Cartesian Formula

    I need a cartesian formula for the parametric equations:
    x=t^2+1
    y=t^2-t
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  2. #2
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    Quote Originally Posted by anon12345 View Post
    I need a cartesian formula for the parametric equations:
    x=t^2+1 .... (1)
    y=t^2-t .... (2)
    From (1): t = \pm \sqrt{x - 1}

    From (2): 0 = t^2 - t - y \Rightarrow t = \frac{1 \pm \sqrt{1 - 4y}}{2} using the quadratic formula.

    Therefore \pm \sqrt{x - 1} = \frac{1 \pm \sqrt{1 - 4y}}{2}

    etc.
    Last edited by mr fantastic; May 5th 2008 at 09:40 PM. Reason: Misread y = t^2 - t as y = t^2 - 1
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  3. #3
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    I've already determined that y=x-2t from subtracting the 2 equations however that is not a cartesian representation because of the t.
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  4. #4
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    Quote Originally Posted by anon12345 View Post
    I've already determined that y=x-2t from subtracting the 2 equations however that is not a cartesian representation because of the t.
    Sorry, I misread the question. I've edited my reply. Please take another look.
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