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Parametric Equation to Cartesian

  1. Sep 5, 2011 #1
    1. The problem statement, all variables and given/known data
    Find a Cartesian equation relating x and y corresponding to the parametric equations

    [itex]x = \frac{2t}{t^3+1}[/itex]

    [itex]y = \frac{9t^2}{t^3+1}[/itex]

    [itex]t \neq -1 [/itex]

    Write your answer in the form [itex]P(x,y)=0[/itex],
    where [itex]P[/itex] is a polynomial in [itex]x[/itex] and [itex]y[/itex] such that the coefficient of [itex]x^3[/itex] is [itex]729[/itex].

    2. The attempt at a solution

    So I already have the second part of the question done which is finding the tangent line at a point, which I solved using dy/dt and dx/dt. I just cannot for the life of me figure out how to start this problem. I have tried solving for t and that has failed miserably. If anyone could just give me a little aid on how to get started, I could most likely solve it from there. Cheers.
    Last edited: Sep 5, 2011
  2. jcsd
  3. Sep 5, 2011 #2


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    Divide y by x to get t = (2/9)(y/x) and put that in for the t's.
  4. Sep 5, 2011 #3
    Many thanks friend. Got this solved.
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