added comment

documents/math-minimal-distance-to-cubic-function/math-minimal-distance-to-cubic-function.tex

@@ -422,8 +422,10 @@ take the same approach as in Equation \ref{eq:minimizingFirstDerivative}:
 \end{align}
 
 \todo[inline]{Although general algebraic equations of degree 5 don't
-have a closed-form solution, the special structure might give the
-possibilty to find a closed form solution. But I don't know how.}
+have a solution formula, the special structure might give the
+possibilty to find a closed form solution. But I don't know how.
+
+This is a first-order nonlinear ordinary differential equation - does this help?}
 
 \subsection{Number of points with minimal distance}
 As there is an algebraic equation of degree 5, there cannot be more