Find a Cartesian equation relating $x$ and $y$ corresponding to the parametric equations $$x=\frac{2 t}{1+t^3}\quad y=\frac{9 t^2}{1+t^3}\quad t\ne-1$$ Write your answer in the form $$P(x,y)=0$$ where $P(x,y)$ is a polynomial in $x$ and $y$ such that the coefficient of $x^3$ is 729.
Answer: $=0$

Find the equation of the tangent line to the curve at the point corresponding to $t=1$.
Answer: $y=$