I am trying to plot the following curve using Matlab:
$$\frac{(x-x_0)^2}{A^2} +\frac{(y-y_0)^2}{B(y)^2}=1$$
where $A$ is constant and $B$ is a function of $y$ whose values are given on a table $(y_k,B(y_k))$.
I have already written $x$ as a function of $y$: for each value $y$ within some known range, compute the two possible values of $x$ and plot it if it is real.
I'm trying to find a more elegant way to plot it, but I can't visualize a proper ellipse-like parametrization for any given $B(y)$ whose analytic representation might not be entirely known (I mean I can intepolate for some value if necessary).